EP0036296A2

EP0036296A2 - Method of and apparatus for applying substances to a surface

Info

Publication number: EP0036296A2
Application number: EP81301031A
Authority: EP
Inventors: Allan Robert Willett
Original assignee: PRINTOS BV
Current assignee: PRINTOS BV
Priority date: 1980-03-14
Filing date: 1981-03-12
Publication date: 1981-09-23
Also published as: CA1153636A; ES8307542A1; ES500366A0; DK113681A; EP0036296A3

Abstract

The invention provides a method of and apparatus for applying two or more substances to a surface. According to the invention a plurality of nozzle means (111, 111') each having a plurality of aligned nozzles (113, 113') and each connected to a different source (119) of a plurality of different substances, are controlled by control means (123,125) to project droplets of the substances onto a surface in a predetermined pattern and so that the positions on said surface occupied by one of said substances will also be occupied by another said substance.

Description

This invention relates to a method of and apparatus for applying substances to a surface.
There are occasions when it is necessary or desirable to apply two or more substances to a surface. For example, many adhesives either require activation as by being moistened with water or another substance or are of the two component type, e.g., comprising the adhesive and a catalyst or hardener, the two components of which need to be brought together at the time of use. In some printing or colouring operations, particularly when printing on non-porous surfaces such as plastics containers, it may be desirable to apply a base coat or layer, e.g., of an adherent absorbent material, which will provide a suitable surface for the reception of the ink or colour. It is also envisaged that printing may be effected by applying to a said surface different substances which will react together to produce different effects, e.g., different surface effects or different colour effects, or to bring together substances having different properties such as a printing or colouring material and a material which is capable of receiving an electrical or magnetic charge, e.g., for the printing of bar or other codes of different colours and/or which are capable of accepting electrical or magnetic signals and which are thus suitable for use with suitable encoding and decoding means.
The present invention has as its object to provide a method of and apparatus for applying two or more substances to a surface.
The present invention provides a method of applying two or more substances to a surface, the method comprising applying at least two substances to the surface, at least one of said substances being applied to the surface by projecting droplets thereof onto the surface in a predetermined pattern, each of the positions on said surface occupied by a said droplet of the one substance also being occupied by another said substance.
The present invention also provides apparatus for applying two or more substances to a surface, the apparatus comprising at least two means for applying at least two substances to a surface, at least one of said means comprising means for projecting droplets of one of said substances onto a said surface and means for controlling the projection of said droplets in a predetermined pattern, the arrangement being such that the position on the surface occupied by each droplet of the one substance will also be occupied by another said substance.
According to a first embodiment of the invention one of said substances is applied to the surface as a coating or layer whilst at least one other said substance is applied to the surface by projecting droplets thereof onto the surface in a predetermined pattern. Thus the apparatus may comprise as one of said applying means suitable coating means and as the other said applying means said droplet projecting means. The method and apparatus according to this first embodiment are particularly suited to applying to a surface, e.g., a surface of a label or packaging tape, an adhesive and an activating agent or catalyst or hardener therefor, e.g., a gum and water for activating the gum. It is immaterial whether it is the adhesive or the activating agent, catalyst or hardener which is applied in the form of droplets, although in the case of gum and water it will probably be more economical to save on gum by applying this in droplet form in a predetermined pattern which will provide a sufficient coverage to give a required bond strength and to subsequently apply the water over the whole of the surface.
Thus the apparatus according to said first embodiment may comprise a plurality of nozzles, means for effecting relative movement between said nozzles and a said surface, means for supplying adhesive or an activating agent under pressure to said nozzles and valve means associated with each of said nozzles for controlling the supply of adhesive or activating agent thereto. Likewise the method according to said first embodiment may comprise providing a plurality of nozzles, effecting relative movement between said nozzles and said surface, supplying adhesive or an actuating agent under pressure to said nozzles and actuating valve means associated with each of said nozzles so as to control the supply of adhesive or activating agent thereto.
Preferably each of said valve means is an electrically operated valve, e.g., a solenoid valve, and electronic control means is provided for selectively operating said valve means.
Said plurality of nozzles may be provided in a common nozzle block and are preferably aligned in a single row in spaced relation to one another so that they extend laterally of the direction of relative movement between the nozzles and said surface.
Each nozzle and its associated valve means is preferably such that when the valve means is actuated adhesive or activating agent will issue from the nozzle in the form of a small jet of short duration to provide a droplet which will form a spot of adhesive or activating agent on a surface onto which it is directed. In this way and by selectively controlling the actuation of said valve means in timed relation to the relative movement between the nozzles and a said surface it is possible to apply spots of adhesive or activating agent to the surface in a required pattern, thus enabling only as much adhesive or activating agent to be applied as is required in any particular instance and consequent savings to be made in adhesive or activating agent.
Said means for effecting relative movement between said nozzles and a said surface may comprise any suitable conveyor or transport means for conveying or transporting an object, e.g., a lable or a length of tape, providing said surface past said nozzles.
According to another embodiment of the present invention there is provided a method of applying two or more substances to a surface, the method comprising projecting droplets of at least two said substances onto said surface in a predetermined pattern or arrangement and so that the position on said surface occupied by each droplet of a first said substance will also be occupied by a droplet of another said substance.
The apparatus according to this latter embodiment may comprise means for projecting droplets of at least two said substances onto a said surface and means for controlling the projection of said droplets, the arrangement being such that the droplets can be projected onto a said surface in a predetermined pattern or arrangement and with the position on said surface occupied by each droplet of a first said substance also occupied by a droplet of another said substance.
The means for projecting droplets of the at least two substances may comprise separate nozzle means for each said substance. Said separate nozzle means may be arranged and controlled to direct droplets of the at least two substances to each said position on a said surface either simultaneously or at spaced intervals.
Each said nozzle means may comprise a single nozzle having suitable valve means, e.g., a piezeoelectric valve, associated therewith by way of which it is connected to a source of a said substance under pressure, whereby the substance can be caused to issue from the nozzle as a continuous streamof droplets, and means may be provided for effecting relative movement between the nozzle means and a surface onto which the substance is to be directed and for selectively electrically charging said droplets and for selectively creating an electrical field or fields whereby said droplets can be selectively directed either to a required position on said surface or to a drain, e.g., for return to said source.
According to a preferred embodiment, however, each said nozzle means comprises a plurality of nozzles each of which is connected or connectable to a source of a said substance under pressure and each of which has valve means associated therewith for controlling the supply of the substance thereto and the apparatus comprises means for effecting relative movement between the nozzle means and a said surface.
Each said valve means may be an electrically operated valve, e.g., a solenoid valve, and electronic control means may be provided for selectively operating the valve means.
Said plurality of nozzles of each nozzle means may be provided in a common nozzle block and are preferably aligned in a single row in spaced relation to one another so that they extend laterally of the direction of relative movement between the nozzle means and said surface. In addition, each nozzle means may have the same number of nozzles therein and the corresponding nozzles in the different nozzle means may be aligned in the direction of relative movement between the nozzle means and the surface, the control means being such that the valve means of corresponding nozzles of different nozzle means can be actuated in timed relation to one another and to the speed of relative movement between the nozzle means and the surface that the droplets projected by the corresponding nozzles will occupy the same position on the surface.
The invention will be more particularly described with reference to the accompanying drawings, in which:-

Figure 1 is a diagrammatic side elevation of a label applying machine incorporating apparatus according to one embodiment of the present invention,
Figure 2 is a fragmentary view of a modification of the machine of Figure 1,
Figure 3 is a diagrammatic view on a larger scale of nozzle means forming part of the apparatus of Figure 1, and
Figure 4 is a fragmentary enlarged view of one of the nozzles of the apparatus of Figure 3.
Figure 5 is a diagrammatic perspective view of another embodiment of apparatus according to the present invention, this time installed on a conveyor line, and
Figure 6 is an exploded view on a larger scale of one of the nozzle means forming part of the apparatus of Figure 5.

Referring to Figure 1 of the drawings it will be seen that the label applying machine illustrated therein comprises a pair of drive rollers 1 for drawing a tape or web 2, e.g., of gummed paper, from a roll 3 and passing it to a rotary cutter 4 which cuts the tape or web 2 into labels 5. The cut labels 5 are fed by drive rollers 6 to a conveyor 7 which carries them past nozzle means 8 to a label applying station 9. The conveyor 7 comprises a plurality of narrow endless belts which are spaced from one another and which pass around spaced drive and idler rollers 10 and 11 respectively. Suitable vacuum or suction means (not shown) is provided for holding the labels 5 on the conveyor 7 until they reach the label applying station 9. At the station 9 a series of air jet nozzles indicated diagrammatically by arrows 12 ejects each label from the conveyor 7 and onto an article (not shown) to which the label is to be applied.
In the modification shown in Figure 2 the roll 3 of tape or web 2 is replaced by a magazine 13 for holding pre-cut labels 5a and vacuum transfer means 14 is provided for feeding the pre-cut labels 5a direct to the label drive rollers 6.
The nozzle means 8 is shown in Figures 3 and 4 and serves either to apply adhesive to the labels 5 if these do not already have adhesive thereon or to apply an activating agent, such as water or a suitable catalyst, to adhesive on the labels 5 if these have been pre-coated with adhesive.
Referring now to Figures 3 and 4 it will be seen that the nozzle means 8 comprises a nozzle block 15 having a plurality of nozzles 16 formed therein, a plurality of electrically operated solenoid valves 17 each of which is connected to a nozzle 16 by means of a conduit 18, a terminal block 19 to which the solenoid valves 17 are electrically connected and which is itself electrically connected to suitable electronic control means (not shown), a manifold 20 to which each of the solenoid valves 17 is connected by means of a conduit 21, and a reservoir 22 which can be pressurized to supply adhesive or an activating agent under pressure to the manifold 20 by way of a conduit 23.
The nozzles 16 are arranged in the nozzle block 15 in a single row in alignment with and at equally spaced intervals from one another, said row of nozzles 16 extending laterally of the path of travel of the labels 5. As will be seen from Figure 4 each of the nozzles 16 comprises an insert 24 in a bore 25 in the nozzle block 15, the insert 24 having a bore 26 therein which provides the nozzle orifice, a counterbore 27 at one end of the bore 26 which provides a shroud around the outlet end of the bore 26 and a counterbore 28 at the other end of the bore 26 which receives one end of a conduit 18. The shroud 27 has been found to be useful particularly when adhesives containing volatile solvents are used because solvent vapour given off by the adhesive tends to collect therein and so assist in preventing drying of the adhesive in the nozzle bore 26.
The solenoid valves 17 are commercially available fast-acting solenoid valves having a response time of from 1₀0 microseconds to 50 milliseconds, preferably a response time of 3 milliseconds and a cycle time of about 1₀ milliseconds. The valves 17 may be either single-acting spring return valves or double-acting valves.
Although not shown in the drawings, the nozzle block 15 and the manifold 20 can be mounted on opposite sides of a base plate and the solenoid valves 17 and the terminal block 18 can be mounted therebetween to provide a very neat and compact arrangement.
Each of the said nozzles 16 and its associated solenoid valve 17 is preferably such that when the valve 17 is actuated adhesive or an activating agent will issue from the nozzle 16 in the form of a small jet of short duration which will form a spot of adhesive or activating agent on a label 5, whilst said electronic control means is preferably programmable to selectively actuate the valves 17 so that spots of adhesive or activating agent can be applied to each label 5 either so as to cover substantially the whole of that surface thereof directed towards the nozzles 16 or in a required pattern on said surface.
The ability to apply adhesive in a required pattern on each label 5 is particularly advantageous because it enables a minimum amount of adhesive to be used and considerable cost savings to be made, the cost of adhesive being significant when very large numbers of labels need to be applied.
Referring now to Figures 5 and 6 it will be seen that the embodiment illustrated therein comprises two nozzle means indicated generally as 111 and 111¹ which respectively comprise a plurality of nozzles 113, 113¹ for projecting a substance onto a side surface of a container 115 as the container travels on a conveyor 117. The nozzle means 111, 111¹ are connected by separate conduits 121, 121¹ with separate sources 119 (only one of which is shown) of two different substances under pressure so that a different one of said substances will be fed to each of the nozzle means 111, 111¹. A microprocessor control means 123 selectively controls the projection of droplets of the two different substances from the nozzles 113, 113¹ onto container 115 in response to a message input device 125 which can be programmed by an operator. Photocells 127, 127¹ are associated with the nozzle means 111, 111¹ respectively for detecting the leading edge of the container 115 as it passes in front of the respective nozzle means 111, 111¹, the photocells 127, 127¹ being connected to the control means 123 and being adapted to provide the control means 123 with signals indicative of the position and/or speed of travel of the container 115 along the conveyor 117.
Figure 6 shows only the nozzle means 111 although it will be understood that the nozzle means 111¹ is identical thereto. As shown in Figure 6, the nozzle means 111 has a plurality of nozzles 113 provided in a common nozzle block 131. Preferably, the nozzles are arranged in a single column in alignment with and at equally spaced intervals from one another, although other arrangements are possible such as arranging the alternate nozzles in two columns parallel with one another. Also, the corresponding nozzles 113,113¹ of the two nozzle means 111,111¹ are horizontally aligned with one another, i.e., are aligned in the direction of travel of the container 115'
Each nozzle 113 comprises a single aperture for the passage of a said substance. Alternatively, each nozzle 113 can comprise a plurality of apertures which provide the same cross-sectional area as the single aperture. The nozzles 113 are preferably jeweled orifice nozzles, such as the sapphire jewels used in acetylene torches and the like. The diameter of the jeweled orifice of each nozzle may be in the range of 0.025mm to 0.215mm, and preferably in the range of 0.145mm to 0.185mm.
Each nozzle 113 is set in a nozzle block 131 preferably made of an inert material such as a suitable plastics. The nozzle block 131 may have a series of generally circular recesses therein for receiving the nozzles 113. The distance between the centre of the orifice of each nozzle 113 when the orifices are vertically aligned may be in the range of O.Olmm to 5.0mm and preferably is in the range of 0.05mm to 0.50mm.
The nozzle block 131 is backed by a longitudinal strip 127. A series of rigid tubes 149 leading from the nozzles 113 project outward from the side of strip 147 opposite nozzle block 131. Tubes 149 and hence nozzles 113 are each in fluid communication with the output port 151 of a valve 153 by means of a fluid conduit 150. Conduits 150 are of any suitable commercially available conduit,e.g., of metal or plastics material and are preferably in the range of 0.127mm to 1.270mm in diameter.
Valves 153 may be any suitable commercially available fast acting valve having an electrical cycle time in the range of from 0.1 to 10 milliseconds, preferably in the range of 1.0 to 4.5 milliseconds. Suitable valves can be either a single-acting spring return, a double acting electromagnetic solenoid valve or a piezeoelectric valve.- Preferably a single-acting spring return solenoid valve is used. Such a valve 153 typically has an output port 151 and an input port 155. Wires 173, 175 run from the solenoids of valves 153 to the control circuit of the control means 123 by means of a data cable 166.
The input ports 155 of valves 153 are each in fluid communication with a common manifold 177 by means of fluid conduits 179 which are similar to conduits 150. Manifold 177 communicates with the pressurized source 119 by means of line 121. The components of the nozzle means 111 are conveniently housed within a generally rectangular box including bottom 181, end pieces 183, 185, and top 187. End piece 183 has a centrally located slot 189 adapted to receive nozzle block 131.
The operation of the present apparatus will now be described. The photocell 127 mounted on the nozzle means 111 detects the leading edge of a container 115 which is moving along conveyor 117. An electrical signal is fed to the control means 123 which has been programmed by the operator through input device 125 to direct the projection of droplets of a first substance in a desired pattern or arrangement, e.g., in a desired character message. The control means 123 is electrically connected to solenoid valves 153 by the wires 173, 175.
Valves 153 are thus selectively and intermittently actuated by the electrical control means to allow said first substance to flow from manifold 177 through output ports 151 to nozzles 113 and onto the surface of the container 115. The selective actuation of the valves 153 by the control means 123 as the container 115 moves past the nozzle means 111 allows droplets of said first substance to be projected onto container 115 in a predetermined dot-matrix format. In like manner, when.the leading edge of container 115 is detected by the photocell 127¹ a further electrical signal will be fed to the control means 123 and the nozzle means 111¹ will be actuated in similar manner to the nozzle means 111 so that droplets of a second substance are projected onto the container 115 in the same pattern or arrangement as the first substance and so that the droplets of the second substance occupy the same positions on the container 115 as the droplets of the first substance.
It will be readily understood that if desired one or more further nozzle means could be provided for projecting droplets of one or more further substances onto the container 115. For example a third nozzle means could be provided downstream of the nozzle means 111¹ for projecting onto the container 115 droplets of a third substance from a pressurized source thereof. The third nozzle means will again be controlled by the control means 123. The three nozzle means can be so controlled that droplets of all three substances are projected at the same positions on the container 115 or so that droplets of the second substance are projected to the positions occupied by some of the droplets of the first substance whilst droplets of the third substance are projected to the positions occupied by the remainder of the droplets of the first substance. This latter enables some interesting effects to be obtained using substances which react differently to give different effects, e.g., different surface finishes or different colour changes. For example, the three substances may be such that the first and second and the first and third substances react to give different colours and the control means may be programmed so that the projected droplets form alpha-numeric characters in a dot-matrix format wherein some of the dots comprise the first and second substances and are hence of one colour whilst others of the dots comprise the first and third substances and are of the other colour.

Claims

1. A method of applying two or more substances to a surface, the method comprising applying at least two substances to the surface, at least one of said substances being applied to the surface by projecting droplets thereof onto the surface in a predetermined pattern, each of the positions on said surface occupied by a said droplet of the one substance also being occupied by another said substance.

2. A method of applying two or more substances to a surface, the method comprising projecting droplets of at least two said substances onto said surface in a predetermined pattern and so that the position on said surface occupied by each droplet of a first said substance will-also be occupied by a droplet of another said substance.

3. A method according to claim 1, wherein one of said substances is applied to the surface as a coating and at least one other said substance is applied to the surface by projecting droplets thereof onto the surface in a predetermined pattern.

4. A method according to claim 3, wherein first the surface is coated with one of said substances and then at least one other said substance is applied thereover by projecting droplets thereof.

5. A method according to claim 2, wherein the droplets of said at least two substances are directed to each said position substantially simultaneously.

6. A method according to claim 2, wherein droplets of one of said substances are first projected onto said surface in a predetermined pattern and then droplets of at least one other said substance are projected onto said surface so that the droplets of said at least one other substance occupy the same positions on the surface as the droplets of the one substance.

7. A method according to any one of the preceding claims, which comprises causing each said substance which is to be projected onto said surface in the form of droplets to issue from a nozzle as a continuous stream of droplets, effecting relative movement between the nozzle and said surface, selectively electrically charging said droplets, and selectively creating an electrical field or fields whereby said droplets are selectively directed either to a required position on said surface or to a drain.

8. A method according to any one of the preceding claims 1 to 6, which comprises causing each said substance which is to be projected onto said surface in the form of droplets to issue from nozzle means comprising a plurality of nozzles, effecting relative movement between the nozzle means and said surface, and selectively controlling the issue of droplets from each said nozzle of the nozzle means so that the droplets are projected onto said surface in required positions.

9. A method according to claim 8, insofar as this is dependant upon claim 2, which comprises arranging the nozzles of each said nozzle means in-spaced alignment laterally of the direction of relative movement between the nozzle means and said surface and with the corresponding nozzles of the different nozzle means aligned in the said direction of relative movement, and so controlling the projection of droplets of the different substances from the corresponding nozzles of the different nozzle means that the droplets will be caused to occupy the same position on the surface.

10. A method according to claim 9, which comprises producing signals indicative of the position of said surface relative to each of the nozzle means and using said signals to control the projection of-droplets of the different substances from the nozzle means.

11. Apparatus for applying two or more substances to a surface, the apparatus comprising at least two means for applying at least two substances to a surface, at least one of said means comprising means for projecting droplets of one of said substances onto a said surface and means for controlling the projection of said droplets in a predetermined pattern, the arrangement being such that the position on the surface occupied by each droplet of the one substance will also be occupied by another said substance.

12. Apparatus according to claim 11, comprising as one of said applying means coating means for coating a said surface with one of said substances.

13. Apparatus according to claim 11, comprising means for projecting droplets of at least two said substances onto a said surface and means for controlling the projection of said droplets, the arrangement being such that the droplets can be projected onto a said surface in a predetermined pattern and with the position on said surface occupied by each droplet of a first said substance also occupied by a droplet of another said substance.

14. Apparatus according to claim 11, 12 or 13, comprising at least one nozzle, means for causing one of said substances to issue from said nozzle as a continuous stream of droplets, means for effecting relative movement between said nozzle and a said surface, means for selectively electrically charging said droplets, and means for selectively creating at least one electrical field whereby said droplets are selectively directed either to a required position on said surface or to a drain.

15. Apparatus according to claim 11, 12 or 13, wherein the or each said droplet producing means comprises nozzle means and each said nozzle means comprises a plurality of nozzles, means for effecting relative movement between the nozzle means and said surface, and means for selectively controlling the issue of droplets from each said nozzle of the nozzle means so that the droplets are projected onto said surface in required positions.

16. Apparatus according to claim 15, insofar as this is dependant upon claim 13, wherein the nozzles of each said nozzle means are in spaced alignment laterally of the direction of relative movement between the nozzle means and said surface and with the corresponding nozzles of the different nozzle means aligned in said direction of relative movement, and control means for so controlling the projection of droplets from corresponding nozzles of the different nozzle means that the droplets will be caused to occupy the same position on the surface.

17. Apparatus according to claim 16, comprising means for producing signals indicative of the position of said surface relative to each of the nozzle means and means for feeding said signals to said control means.

18. Apparatus for applying or activating adhesive on a surface, the apparatus comprising a plurality of nozzles for projecting droplets of adhesive or activating agent onto a said surface, means for effecting relative movement between the nozzles and a said surface, means for supplying adhesive or an activating agent under pressure to said nozzles, valve means associated with each of the nozzles for controlling the supply of adhesive or activating agent thereto, and control means for controlling the actuation of said valve means.

19. A method of applying or activating adhesive on a surface, the method comprising providing a plurality of nozzles for projecting droplets of adhesive or activating agent onto a said surface, effecting relative movement between the nozzles and the said surface, supplying adhesive or an activating agent under pressure to said nozzles, actuating valve means associated with each of the nozzles to control the supply of adhesive or actuating agent thereto, and controlling the actuation of said valve means.