[0001] This invention relates to a method for applying adhesives to a substrate and is a
divisional of copending European Patent Application No. 83304565.1.
[0002] The present invention has as its object the provision of a method for applying droplets
of an adhesive to a surface utilising an ink jet printer apparatus.
[0003] Accordingly, the present invention provides a method for applying droplets of an
adhesive composition to a surface via one or more nozzles, characterised in that the
nozzle is a nozzle of an ink jet printing apparatus.
[0004] The jet printing apparatus for present use preferably is of the continuous jet type
which comprises one or more nozzles each adapted to produce a continuous jet of adhesive
which is broken up into a single stream of substantially uniformly spaced apart and
substantially uniformly sized droplets of adhesive and electrostatic or other means
for directing the individual droplets to selected positions on a surface or to a drain
or gutter.
[0005] According to a preferred embodiment of the invention there is provided a method for
applying an adhesive composition to a surface characterised in that the adhesive applying
means comprises means for directing a continuous stream of drops of the adhesive in
a direction to traverse and not impinge on a surface to which the adhesive is to be
applied, means for effecting relative movement between the said stream of drops and
the said surface in a direction perpendicular to the direction of travel of the stream
of drops, means for selectively and variably electrically charging the drops in the
said stream, and means for establishing a steady electric field about the path of
travel of said stream of drops for deflecting the electrically charged drops onto
said surface.
[0006] The invention will be more particularly described with reference to the accompanying
drawings, in which:-
Figure 1 is a diagrammatic side elevation of one embodiment of labelling apparatus
utilising the adhesive application method of the present invention,
Figure 2 is a diagrammatic front elevation of the apparatus shown in Figure 1,
Figure 3 is a diagrammatic side elevation,of another embodiment of labelling apparatus,
Figure 4 is a fragmentary enlarged detail view of a modification of the apparatus
shown in Figure 3,
Figure 5 is a side elevation of another embodiment of labelling apparatus and
Figure 6 is a diagrammatic representation of one form of adhesive applying means suitable
for use with the labelling apparatus of Figure 1 to 5.
[0007] Referring to Figures 1 and 2 of the drawings it will be seen that the apparatus illustrated
therein comprises a plain paper label supply station 1, an adhesive applying station
2 and a label applying station 3.
[0008] At the label supplying station 1 there is provided a label magazine 4 adapted to
contain a stack of plain paper labels and a vacuum label extractor 5 which is connected
to a source of vacuum. The extractor 5 is intermittently controllable by a cutoff
valve 6 to exert vacuum pressure on the lowermost label in the magazine 4 and draw
this from the magazine onto an endless conveyor 7. As will be seen more clearly from
Figure 2, the endless conveyor 7 comprises a plurality of parallel endless belts 8
having spaces 9 therebetween, the extractor nozzles 5a of the label extractor 5 being
aligned with the spaces 9 between the endless belts 8. The endless belts 8 extend
around a driven roller 10, idler rollers 11, 12 and 13 and a tensioning roller 14.
The driven roller 10 is driven by a drive belt 15 which extends round a clutch and
brake mechanism 16 which in turn is driven through a drive belt 17 by a motor 18.
The idler rollers 11 and 12 are hollow and have apertures 19 in the peripheral wall
thereof which are aligned with the spaces 9 between the endless belts 8. The interiors
of the idler rollers 11 and 12 are connected to a source of vacuum so that vacuum
will be exerted through the apertures 19 to maintain the labels in contact with the
endless belts 8 as these pass round the rollers 11 and 12.
[0009] From the label supply station 1 the labels are carried on the conveyor 7 around the
idler roller 12 to the adhesive applying station 2. The labels are maintained in contact
with the conveyor 7 by establishing an area of low pressure 20 beneath the conveyor
7. This exerts vacuum pressure on the labels through apertures 21 provided in a platen
22 over which the conveyor 7 passes, the apertures 21 being aligned with the spaces
9 between the belts 8 of the conveyor 7.
[0010] From the adhesive applying station 2 the labels are transported on the conveyor 7
around the idler roller 11 to the label applying station 3. At the label applying
station 3, the conveyor 7 travels over a platen 24 which, like the platen 22, has
apertures 25 therein which are aligned with the spaces 9 between the belts 8. Some
of the apertures 25 are connected to a source of vacuum for maintaining the labels
in contact with the conveyor 7, whilst others of the apertures 25 are connected to
a source of air under pressure 23 for transferring the labels from the conveyor 7
onto articles to be labelled. Although not shown in the drawings, the articles to
be labelled are transported on a suitable conveyor which extends parallel to the reach
7a of the conveyor 7 at the label applying station.
[0011] The label applying apparatus illustrated in Figures 1 and 2 may be adapted for either
continuous or intermittent operation. Where it is adapted for continuous operation,
then the labels will travel continuously from the label supply station 1 to the label
applying station 3 and will have adhesive continuously supplied thereto at the adhesive
applying station 2. Where the apparatus is designed for intermittent operation, then
the labels will be transported from the label supplying station 1 to the adhesive
applying station 2 where their travel will be interrupted whilst the adhesive is applied
thereto. The travel of the labels can be interrupted either by stopping the conveyor
7 or by providing suitable stops which can be extended through the spaces 9 between
the belts 8 at the adhesive applying station 2. The leading edge of each label engages
the extended stops so that the label skids on the conveyor 7 whilst the adhesive is
applied thereto. The stops are then retracted to allow the label to continue its travel.
[0012] The labelling apparatus illustrated in Figures 3 and 4 is for applying labels to
bottles, cans or other cylindrical articles. As will be seen, the apparatus comprises
a label magazine 26, a feed roller 27 or other suitable feed mechanism for feeding
the labels one at a time to an adhesive applying station 28, a conveyor 29 for transporting
bottles or other similar articles 30 to a label applying station 31, and a wrap-around
belt 32 for wrapping the labels with adhesive thereon around the articles 30. The
adhesive applying station 28 comprises a vacuum box or like means 33 having an apertured
wall on which the labels are held by vacuum pressure whilst adhesive is applied thereto
by a nozzle 34.
[0013] The labelling machine illustrated in Figure 5 is for use with labels which are printed
on and cut from a web and comprises a support 35 on which is mounted a supply reel
36 of printed web, a coder 37, label cutting means 38, a web matrix take-up reel 40,
adhesive applying means 41 and label applying means 42.
[0014] Where the labels printed on the web 43 are to have a code marking applied thereto
by the coder 37, which coder may be of any suitable form and may comprise, for example,
suitable ink jet printing means, then the web 43 is taken off the supply web 36, over
a tension roller 44, around a guide roller 45, through suitable coder registration
means 46, past coder 37 so that code markings can be applied to the labels and on
to suitable cutter registration means 47. Where code marking of the labels is not
required, then the web 43 is taken from the supply reel 36 around a tension roller
48 and then direct to the cutter registration means 47. From the cutter registration
means 47 the label web passes by way of driven feed rollers 49 to the cutting means
38. The cutting means 38 comprises opposed die cutting rollers which are adapted to
sever the labels completely from the web matrix 43a but to leave them retained in
the web matrix. From the cutting means 39 the web passes between guide plates 50 to
a vacuumised label transport 51 on which the labels are retained by suction or vacuum
whilst the web matrix 43a from which the labels are removed continues on and is re-wound
on matrix take-up reel 40. The vacuumised label transport 61 comprises spaced . hollow
perforate rollers 52, one of which is driven, and spaced guide rollers 52a around
which a series of spaced parallel belts 53 extend and means for maintaining the pressure
within the rollers 52 and on the underside of the reach 54 of the belts 53 below atmospheric
so that the labels will be retained on the rollers 52 and belts 53 by vacuum pressure
exerted through the perforations in the rollers 52 and the spaces between the belts
53. The label transport 51 transports the labels from the adhesive applying means
41 to the label applying means 42.
[0015] The continuous jet adhesive applying means is capable of applying adhesive to moving
labels. The label transport 51 may therefore operate continuously as well as intermittently.
Where desired or necessary suitable label sensing means 55 may be provided downstream
of the adhesive applying means 41 for providing a control signal indicative of the
presence of a label and so enabling the label applying means 42 to be suitably controlled.
[0016] Where both the coder 37 and the adhesvie applying means 41 are-of the jet printing
kind, and possibly in other cases also, the control functions required to control
the operation thereof will be the same or similar and accordingly a common control
means, e.g. a common microprocessor based control circuit, may be provided for controlling
the operation thereof.
[0017] The label applying means 42 comprises a perforate grid 56 onto which the labels are
transferred from the label transport 51 and which forms one wall of an air box 57
the interior of which is maintained by a fan 58 at a pressure below atmospheric so
that the labels will be retained on the grid 56 by vacuum pressure. Mounted in the
air box 57 is a manifold 59 which is connected to a source of air under pressure (not
shown) by way of a suitable control valve (not shown). Connected to the manifold 59
are a series of tubes (not shown) the other ends of which communicate with apertures
in the grid 56 through which air under pressure can be applied. to the labels to overcome
the vacuum holding the labels on the grid and transfer the labels onto articles to
be labelled which are transported past the grid 56 on suitable conveyor means (not
shown).
[0018] Said control valve controlling the supply of air under pressure to the manifold 59
may be actuated by suitable control means so as to ensure that the labels are correctly
applied to the articles to be labelled. Such control means may comprise a pair of
photocells or other suitable detectors which are arranged a predetermined distance
apart at locations upstream of the grid 56 and which are adapted to detect articles
to be labelled moving towards the grid 56, means for measuring the time it takes an
article, e.g. the leading edge of the article, to travel the predetermined distance
between the two detectors, means for computing the speed of travel of the article
from said time measurement, and means for actuating said control valve after a suitable
computed time delay so that a label will be correctly applied to the article.
[0019] Whilst the apparatus of Figure 5 has been described in relation to labels which are
die-cut from a web matrix and are retained in the web matrix until they are transferred
to the label transport 51, the apparatus is with only slight modification also suitable
for use with square cut or butt cut labels, i.e. labels which extend the full width
of the web 43 and which are formed by simply transversely cutting the web. For such
butt cut labels the die-cutting rollers 38 are replaced by a suitable cutting knife,
guillotine, or the like and, since there will no longer be a web matrix to carry the
labels onto the label transport 51, a pair of feed rollers or the like are interposed
between the cutting means and the label transport 51 for feeding the labels from the
cutting means to the label transport.
[0020] The adhesive applying means for use in the apparatus of Figures 1 to 5 typically
comprise a nozzle 61 having an inlet 62 whereby it can be connected to a source of
adhesive under pressure (not shown) and piezo electric stimulating means 63, e.g.
in the form of a bimorph or a unimorph. The nozzle 61 is adapted to produce a single
stream 63 of adhesive which under the stimulation of the stimulating means 63 breaks
up into uniformly spaced and uniformly sized drops 65. The line of flight of the droplets
is along a path which is either directed at the surface of the label to which adhesive
is to be applied or, as shown in Figure 6, which traverses and is perpendicular to
the path of travel of a label web 67 extending between a feed roller 68 and a take
up roller 69. The adhesive applying means further comprises a charge electrode or
electrodes 70 for selectively and variably charging the jet of adhesive as or before
it breaks up into the drops 65; and a pair of opposed deflector plates 71 which are
arranged on either side of the path of travel of the drops 65 and are suitably connected
into an electric circuit (not shown) for applying either a positive or negative charge
thereto so that a steady electric field will be established therebetween. With the
device shown in Figure 6, the path of travel of the label web 67 is between the lower
deflector plate 71 and the path of travel of the stream of drops 65.
[0021] When the adhesive application means is in use, the uncharged drops 65 will pass in
a straight line between the deflector plates 71 to the drain or gutter 66, whilst
the charged drops 65 will be deflected onto the surface of the label web 67. By selectively
varying the charge applied to the selected drops 65 and coordinating this with the
speed of travel of the label web 67 the selected drops 65 can be deposited at any
required selected position on the web 67, as indicated at 65a and 65b.
1. A method for applying droplets of an adhesive composition to a surface via one
or more nozzles characterised in that the nozzle is a nozzle of an ink jet printing
apparatus.
2. A method as claimed in claim 1 characterised in that adhesive is fed under pressure
to the nozzle from which the adhesive issues as a single stream, the stream is stimulated
to break up the stream into substantially uniformly sized and spaced apart droplets,
the droplets are selectively charged and passed through a deflecting electric field
whereby the droplets are caused to follow a selected flight path either to a selected
position on the surface or to a catching means.
3. A method as claimed in claim 2 characterised in that the stream of adhesive is
broken up into discrete droplets by means of stimulation of the stream using a piezoelectric
crystal.
4. A method as claimed in claim 2 characterised in that the stream of adhesive passes
one or more charge electrodes for selectively and variably charging the stream of
adhesive as or before it breaks up into the drops; and in that the charged droplets
pass between a pair of opposed deflector plates which are arranged on either side
of the path of travel of the droplets and are suitably connected into an electric
circuit for applying either a positive or negative charge thereto so that a steady
electric field will be established therebetween.
5. A method as claimed in claim 1 characterised in that the ink jet printing apparatus
comprises means for directing a continuous stream of drops of the adhesive in a direction
to traverse and not impinge on a surface to which the adhesive is to be applied, means
for effecting relative movement between the said stream of drops and the said surface
in a direction perpendicular to the direction of travel of the stream of drops, means
for selectively and variably electrically charging the drops in the said stream, and
means for establishing a steady electric field about the path of travel of said stream
of drops for deflecting the electrically charged drops onto said surface.
1. Verfahren zum Aufbringen von Tröpfchen eines Haftstoffes auf eine Oberfläche durch
eine oder mehrere Düsen, dadurch gekennzeichnet, daß die Düse eine Düse eines Farbspritzdruckers
ist.
2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß Haftstoff unter Druck in
die Düse gespeist wird, aus der der Haftstoff als einzelner Strahl austritt, wobei
der Strahl in im wesentlichen gleich große und voneinander getrennte Tröpfchen zerlegt
wird und die Tröpfchen selektiv elektrisch geladen und durch ein ablenkendes elektrisches
Feld geleitet werden, so daß die Tröpchen einem ausgewählten Flugweg entweder zu einer
ausgewählten Position auf der Oberfläche oder zu einer Auffangvorrichtung folgen.
3. Verfahren nach Anspruch 2, dadurch gekennzeichnet, daß der Haftstoff-Strahl durch
Anregung mittels eines piezoelektrischen Kristalls in einzelne Tröpfchen zerlegt wird.
4. Verfahren nach Anspruch 2, dadurch gekennzeichnet, daß der Haftstoff-Strahl eine
oder mehrere Ladungselektroden passiert, um den Haftstoffstrahl während oder vor dem
Zerlegen in Tropfen selektiv und variabel aufzuladen, und daß die aufgeladenen Tröpfchen
zwischen einem Paar gegenüberliegender Ablenkplatten hindurchtreten, die auf jeder
Seite des Flugwegs der Tröpfchen angeordnet sind und derart mit einem elektrischen
Kreis verbunden sind, daß entweder eine positive oder negative Ladung auf sie aufgebracht
werden kann, um ein gleichförmiges elektrisches Feld zwischen ihnen zu bilden.
5. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß der Farbspritzdrucker eine
Einrichtung, um einen kontinuierlichen Strahl aus Tropfen des Haftstoffes so in eine
Richtung zu leiten, daß er zur Seite fliegt und nicht auf eine Oberfläche trifft,
aud die Haftstoff aufgebracht werden soll, eine Einrichtung, um eine relative Bewegung
zwischen dem Tropfenstrahl und der Oberfläche in eine Richtung senkrecht zur Flugrichtung
des Tropfenstrahls zu bewirken, eine Einrichtung, um selektiv und variabel die Tropfen
in dem Strahl elektrisch aufzuladen, sowie eine Einrichtung zum Bilden eines gleichförmigen
elektrischen Feldes um den Flugweg des Tropfenstrahls, um die elektrisch geladenen
Tropfen auf die Oberfläche abzulenken, aufweist.
1. Procédé pour appliquer, à l'aide d'un ou plusieurs gicleurs, des gouttelettes d'une
composition adhésive à une surface, caractérisé en ce que le gicleur est un gicleur
d'une imprimante à jet d'encre.
2. Procédé tel que revendiqué à la revendication 1 caractérisé en ce que l'adhésif
est introduit sous pression dans le gicleur d'où l'adhésif sort sous forme d'un courant
unique, le courant est stimulé de façon à être brisé en des gouttelettes dimensionnées
et espacées de manière essentiellement uniforme, les gouttelettes sont sélectivement
chargées et traversent un champ électrique déviateur, ce qui les oblige à suivre un
trajet de vol choisi les dirigeant vers une position choisie de la surface ou vers
un moyen qui les capte.
3. Procédé tel que revendiqué à la revendication 2, caractérisé en ce que le courant
d'adhésif est brisé en des gouttelettes discontinues sous l'effet de la stimulation
du courant à l'aide d'un cristal piezo-électrique.
4. Procédé tel que revendiqué à la revendication 2, caractérisé en ce que le courant
d'adhésif passe devant une ou plusieurs électrodes de charge qui chargent sélectivement
et de façon variable le courant d'adhésif pendant qu'il se brise en les gouttelettes
ou avant cette rupture; et en ce que les gouttelettes chargées passent entre deux
plaques déflectrices opposées disposées de chaque côté du trajet de déplacement des
gouttelettes et qui sont reliées de façon appropriée pour former un circuit électrique
destiné à leur appliquer une charge positive ou négative de façon à établir entre
les plaques un champ électrique constant.
5. Procédé tel que revendiqué à la revendication 1, caractérisé en ce que l'imprimante
à jet d'encre comprend un moyen pour diriger un courant continu de gouttes de l'adhésif
dans une direction leur permettant de passer devant une surface et non pas de heurter
une surface sur laquelle l'adhésif est à appliquer, un moyen pour effectuer un mouvement
relatif entre ledit courant de gouttes et ladite surface en une direction perpendiculaire
à la direction de déplacement du courant des gouttes, un moyen pour charger sélectivement
et de manière électriquement variable les gouttes dudit courant, et un moyen pour
établir un champ électrique permanent autour du trajet de déplacement dudit courant
de gouttes pour dévier vers ladite surface les gouttes électriquement chargées.