NZ206789A - Production of self-adhesive label sheets - Google Patents

Description

206789 Priority DBto(s)t Complete Specification Filed: Class: £.-3>.S/./P.8i.

Publication Date: , .. J.?. P£C.V185. P.O. Journal, No: No.: Date: NEW ZEALAND PATENTS ACT, 1953 COMPLETE SPECIFICATION METHOD AND APPARATUS FOR PRODUCING LABELS l/WSX DAVID JOHN INSTANCE of Past Heap Farm, Pembury, Tunbridge Wells, Kent, England, a British subject hereby declare the invention for which I / pray that a patent may be granted to me/xx, and the method by which it is to be performed, to be particularly described in and by the following statement: - - 1 - (followed by page la) 20S78 - l<Kr METHOD AND ATPAIIATUO FOR PRODUCING LABELS The present invention relates to a method and apparatus for producing labels, more particularly to a method and 5 apparatus for producing self-adhering lithographically printed labels.

In the packaging field there is a great demand for high quality pre-printed labels for labelling containers of 10 various types. In order to facilitate the packaging and labelling of containers at a fast rate it is generally required that the labels to be attached to the containers be made available in a form in which they are easy to handle and easy to transfer onto the containers for which 15 they are intended. In one convenient arrangement the labels are self-adhesive labels which are carried in series on a web of release material which is wound into a reel.

It is well known in the art to produce reels of self-adhesive labels carried on a release paper for transfer of the labels from the release paper to a container to be labelled.

One process for producing such labels is described in my company's British Patent No. 1420933. This patent describes a process for the production of a continuous reel of self-adhesive labels, wherein the labels are produced as separate flat sheets cut to finished size and 30 stacked, the separate labels are then fed in succession from the stack onto the periphery of a drum and held thereon by vacuum means while being fed to an applicator by which they are coated individually on their reverse sides with a pressure-sensitive adhesive composition, the 35 adhesive is dried by passing the labels through a hot air chamber extending around a substantial part of the ' " '7/ < 7 C periphery of the drum, and the labels are applied, successively by their adhesive coated sides to a continuous web of release paper which moves against said drum and which is then reeled.

However this process has certain disadvantages in that it is difficult to produce a continuous reel of self-adhesive labels in which there is a regular gap between adjacent labels. Generally it is preferred to have a regular gap 10 for ease of application of the labels to containers in a continuous labelling process. The reason for this difficulty is that it is not readily possible to place each successive label accurately onto the periphery of the rotating drum and then subsequently to transfer the labels 15 accurately from the drum to the moving web of release paper to obtain a regular spacing between adjacent labels on the release paper. In addition, accurate alignment of the labels on the release paper can be difficult to achieve because of the difficulties mentioned above which 20 are encountered when transferring the labels from the stack of labels to the release paper. This can result in some of the labels being skew relative to other labels on the reel of release paper. When the labels are subsequently applied to containers from the reel, any 25 labels which are in a skew position on the reel of release paper are inevitably transferred in an out-of-true condition and are therefore mis-aligned on the container to which they are attached. This is unacceptable as it renders the product so labelled unattractive to the 30 consumer.

A further disadvantage of this process is that after coating the reverse sides of the labels with pressure-sensitive adhesive, drying the adhesive and 35 applying the labels by their adhesive coated sides to the continuous web of release paper, one frequently obtains surplus adhesive appearing around the periphery of the 206 78 labels on the release paper. When the release paper is wound into a reel this surplus adhesive adheres to the back of the adjacent layer of release paper and can subsequently interfere with the unwinding of the reel and 5 the application of the labels to containers to be labelled.

The present invention aims to overcome these disadvantages by arranging for the peripheral portions of labels applied to a support web to be removed after the labels have been 10 applied to the support web and before the labels are wound into a reel.

As far as I am aware, in the past the printed matter carried on labels which are in the form of a continuous 15 reel of self-adhesive labels is usually printed on to the labels in a continuous manner by means of flexographic, silk-screen, gravure or letterpress printing methods. However, all these printing.methods have certain disadvantages when preparing printed labels carried in 20 series on a support web intended to be wound into a reel. In particular, it is not possible to produce high quality multi-coloured images with screen-printing, flexographic, or letterpress printing techniques. The very nature of these printing techniques prevents them from being used to 25 print fine screens. Furthermore, printing machines built to process labels on the reel are, of necessity, complicated and expensive to produce.

In addition very fine print cannot easily be reproduced if 30 flexographic or screen printing techniques are used.

As a result of these various disadvantages, it has previously been difficult to obtain labels for containers having high quality print and showing multi-coloured 35 images of high quality, except for labels printed by gravure techniques. However, owing to the high tooling 206 78 costs associated with gravure printing, the use of gravure printing is limited to long printing runs.

Lithographically printed images do not suffer from the 5 disadvantages of printed images prepared by the methods discussed above. The use of lithographically-printed images for the preparation of labels in reel form has, as far as I am aware, never been undertaken on a commercial scale, the main reason being that the printing cylinders 10 used have to be specifically made for each different repeat length of label required. I believe that the problems associated with using lithographic printing processes have only been overcome on prototype equipment which lifts the printing cylinder and stops the web prior 15 to each subsequent printing step.

It is a further aim of the present invention to provide an economic and efficient method of producing lithographically printed labels for continuous application 20 to containers to be labelled.

According to one aspect of the present invention there is provided a method of producing a succession of lithographically-printed self-adhesive labels on a length 25 of release backing material, which method comprises the steps of: (a) producing by lithographic printing a plurality of sheets carrying a desired image, (b) adhering each of the lithographically-printed sheets successively to a support web comprising a self-adhesive backed material carried on a release material, the printed sheets being adhered to the upper surface of the adhesive backed material, (c) cutting through the adhered lithographic sheets and through the adhesive-backed material as far as the release material thereby to form the required labels, and (d) removing the unwanted portions of the printed sheets and the adhesive-backed material adhered thereto from the release material.

Preferably, the release backing material carrying the 10 resultant labels is wound onto a reel after the said unwanted portions have been removed.

Preferably, prior to the cutting of the labels in step (c) above, a transparent plastics film, such as a polyester 15 film, is laminated over the printed sheets carried by the support web. This can enhance the appearance of the finished labels.

In one embodiment of the present process, in step (b) the 20 lithographically printed sheets are adhered to the support web by coating either the upper surface of the support web or the rear face of each label with a heat sealable lacquer, applying the lithographically-printed sheets successively to the support web and then heating the 25 assembly, suitably by passing the assembly between heated rollers, to cause the printed sheets to become adhered to the support web.

According to a further aspect of the present invention 30 there is provided apparatus for producing a succession of lithographically-printed self-adhesive labels on a length of release backing material, which apparatus comprises means for transferring individual lithographically-printed sheets in succession from a stack of such sheets to a 35 support web, the support web comprising a self-adhesive backed material carried on a release backing material, 20678 means for adhering the lithographically-printed sheets to the support web, a cutting device for cutting the adhered lithographic sheets and the self-adhesive backed material to form the required labels on the length of release 5 backing material, and means for removing the unwanted portions of the printed sheets and adhesive-backed material adhered thereto.

Preferably the apparatus includes means for winding the 10 length of release backing material and the labels formed thereon onto a reel.

In one embodiment of the apparatus the means for adhering the lithographically-printed sheets to the support web 15 comprises an applicator for applying adhesive to the upper surface of the support web upstream of the zone at which the printed sheets are brought into contact with the support web, and pressure means located downstream of said zone for urging the printed sheets against the support web.

In an alternative arrangement, the adhesive may be applied to the rear face of each of the lithographically-printed sheets prior to their adhesion to the support web.

In a further embodiment, the means for adhering the lithographically-printed sheets to the support web comprises coating means for applying a heat-sealable lacquer either to the upper surface of the support web or to the rear face of each label, said coating means being 30 located upstream of the zone at which the printed sheets are brought into contact with the support web, and heated pressure means located downstream of said zone for urging the printed sheets against the support web and curing the heat-sealable lacquer. Preferably, the heated pressure 35 means comprises one or more pairs of heated rollers. 206 78 9 The present invention will now be illustrated, by way of example only, with reference to the accompanying drawings,' in which:- Figure 1 shows a diagram of one embodiment of an apparatus in accordance with the invention, and Figures 2 and 3 show diagrams of alternative embodiments of an apparatus in accordance with the present invention.

Referring to Figure 1 there is shown an apparatus for preparing a reel carrying a succession of lithographically-printed labels, the appartus comprising a stack 2 of lithographically-printed sheets 4, printed by conventional 15 lithographic techniques, and which are arranged to be fed individually and successively to a support web 6 unwound under slight tension from a reel 8 via guiding rollers 10. The support web 6 which is used is a double-1ayered material consisting of an adhesive-backed material 14 with 20 the adhesive side of the material being protected by a release backing material 16 such as si 1icone-faced backing paper. Such support webs are commonly referred to as self-adhesive stock or pressure-sensitive stock.

The adhesive-backed material 14 may be composed of paper. Alternatively the adhesive-backed material 14 is transparent and is preferably an adhesive-backed transparent plastics sheet such as for example a polyester, polyethylene or polypropylene sheet. When the 30 adhesive-backed material 14 is transparent, in a preferred form of the invention each sheet 4 is also printed, either lithographically or otherwise, on that surface thereof which has not been lithographically printed as aforesaid.

When the resultant 1ithographically printed labels are 35 applied to transparent containers, the said printed surface of the sheet 4 can be visible through the container. 206789 The individual lithographically-printed sheets are adhered to the upper surface of the adhesive-backed layer of the support web 6 by coating the upper surface of the support web with a suitable adhesive, such as pVA 5 adhesive, and then applying each printed sheet in turn to the upper surface of the support web whereupon the resultant composite is passed through nip rollers 18 which ensure complete adhesion of the lithographically-printed sheets 4 to the support web 6. The adhesive is applied to 10 the support web at a coating station 20 upstream of zone A at which the sheets are brought into contact with the support web. At the coating station adhesive is supplied from a reservoir (not shown) via a conduit 22 to an applicator 24 from which adhesive is expressed on to the 15 upper surface of the support web 6.

In an alternative embodiment instead of applying adhesive to the upper surface of the support web, the adhesive is applied to the rear face of each printed sheet before the sheets are applied to the support web.

After a first sheet has been adhered to the support web, a subsequent sheet is brought into position on the support web immediately behind the first sheet and adhered to the support web in the manner described above. The sheets are 25 transferred individually from the stack 2 of sheets to the support web by suitable transfer means 12. In a preferred arrangement the transfer means includes rotary indexable arms carrying vacuum-actuated suction pads for holding and releasing the printed sheets to be transferred from the 30 stack 2 of sheets to the support web. The support web 6 and the transfer means 12 are arranged so that their relative movement can be adjusted to produce a gap between adjacent sheets, or to produce an overlap between adjacent sheets, or to ensure that adjacent sheets abut. 206789 _ 9 - After passing through the nip rollers 18, the support web 6 and the succession of sheets adhered thereto are conveyed to a die-cutting station 26 where a die cutting roller 27 is arranged to cut through the lithographically 5 printed sheets 4 and through the adhesive-backed layer 14 of the support web 6 to which said sheets have been adhered, but not through the release backing material 16 of the support web 6. Different die-cutters 27 may be used to produce labels of different shapes and sizes. 10 After the required shape has been cut into the said layers of material, the waste portions 28 of the said layers are removed from the release backing material 16 and taken up on a reel 30 while the labels 32 thus produced remain on the release backing material and are wound up into the 15 form of a reel 34 for subsequent removal from the backing material and application to a container to be labelled.

In an alternative arrangement, a heat-sealable lacquer may be used to adhere the lithographically-printed sheets to the support web by applying through coating means the said 20 lacquer either to the upper surface of the support web or to the rear face of each printed sheet, the coating means being located upstream of the zone A at which the printed sheets are brought into contact with the support web, and the heat-sealable lacquer is subsequently cured by passing 25 the resultant assembly of printed sheets and support web through heated pressure means such as heated rollers which are located downstream of zone A.

Instead of the transfer means 12 of Figure 1, it may be 30 preferable as shown in Figure 2 to locate the stack 2 of lithographically printed sheets 4 alongside the pathway travelled by the support web 6 and to use alternative means to transfer sheets from this stack 2 to the support 206 78 9 - to - web 6. A suitable transfer means comprises a carriage 40 which can reciprocably travel on rails 42 from a position above the stack 2 of printed sheets to a position above the support web 6. The carriage is provided with 5 vacuum-actuated suction pads 44 for gripping the printed sheets and a centrally located solenoid-controlled rod 46 which is arranged to urge the printed sheet downwardly onto the support web 6 when the sheet is released from the said suction pads. In use the carriage 40 with the rod 46 10 in a retracted position travels into a position over the stack 2 of printed sheets and by activation of the suction pads 44 picks up the top sheet in the stack. The carriage then conveys the said sheet into position over the support web whereupon the vacuum controlling the suction pads is 15 released and at the same time the rod 46 is activated to urge the printed sheet down into contact with the support web. The rod 46 is then retracted and the carriage returned to its initial position above the stack 2, and the sequence of operations is then repeated to transfer .20 each printed sheet in turn from the stack to the support web.

A still further alternative arrangement for transferring printed sheets to the support web is illustrated 25 diagrammatically in Figure 3. This shows an arrangement in which the support web is caused to travel upwardly over a roller 50 and then to travel in a horizontal direction. Printed sheets 4 are transferred from a stack 2 onto the moving support web as the support web passes over roller 30 50 by means of a stream feeder 52 of known construction. Stream feeders are known in the art and will therefore not be described in detail. However, they include a first series of vacuum-operated suction pads 54 which are arranged to reciprocate in a vertical direction for 206 78 9 lifting a top sheet from a stack of such sheets and a second series of vacuum-operated suction pads 56 which co-operate with the first series of suction pads 54 and reciprocate in a for-and-aft direction to transfer a sheet 5 from the first suction pads 54 to rollers 58 which in turn feed the sheets to the support web 6 as it passes over the roller 50. When using this arrangement incorporating a stream feeder, if an adhesive is to be used to adhere the printed sheets to the support web 6 the adhesive must be 10 applied not to be rear face of the printed sheets, but to the upper surface of the support web, and must be applied to the support web at a location upstream of the roller 50.

It will be appreciated that the present invention provides 15 means of obtaining in economic manner high quality 1ithographically-printed labels in a form highly suited for efficient use in the packaging field for easy application to containers which are to be labelled.

Claims (15)

CLAIMS; mAT #WE CLAIM IS;

1. A method of producing a succession of lithographically-printed self-adhesive labels on a length of release backing material, which method comprises the steps of: 5 (a) producing by lithographic printing a plurality of sheets carrying a desired image, (b) adhering each of the 1ithographically-printed 10 sheets successively to a support web comprising a self-adhesive backed material carried on a release material, the printed sheets being adhered to the upper surface of the adhesive backed material, 15 (c) cutting through the adhered lithographic sheets and through the adhesive-backed material as far as the release material thereby to form the required labels, and (d) removing the unwanted portions of the printed 20 sheets and the adhesive-backed material adhered thereto from the release material.

2. A method according to Claim 1, wherein after step (d) the release backing material carrying the resultant 25 labels is wound onto a reel.

3. A method according to Claim 1 or 2, wherein prior to the cutting of the labels in step (c), a transparent plastics film, such as a polyester film, is laminated over 30 the printed sheets carried by the support web. 206789

4. A method according to any one of Claims 1 to 3, wherein in step (b) the lithographically printed sheets are adhered to the support web by coating either the upper surface of the support web or the rear face of each label 5 with a heat sealable lacquer, applying the lithographically-printed sheets successively to the support web and then heating the assembly, to cause the printed sheets to become adhered to the support web. 10

5. A method according to Claim 4, wherein the said assembly is heated by passing it through heated rollers.

6. A method according to any preceding claim, wherein the self-adhesive backed material is transparent and prior to the adhering of the sheets in step (b), on each sheet that surface thereof which is to be adhered to the support web is printed with a desired image.

7. Apparatus for producing a succession of lithographically-printed self-adhesive labels on a length 15 of release backing material, which apparatus comprises means for transferring individual lithographically-printed sheets in succession from a stack of such sheets to a support web, the support web comprising a self-adhesive backed material carried on a release backing material, 20 means for adhering the lithographically-printed sheets to the support web, a cutting device for cutting the adhered lithographic sheets and the self-adhesive backed material to form the required labels on the length of release backing material, and means for removing the unwanted 25 portions of the printed sheets and adhesive-backed material adhered thereto.

8. Apparatus according to Claim 7, further including means for winding the length of release backing material 30 and the labels formed thereon onto a reel. - 14 - 206 78

9. Apparatus according to Claim 7 or 8, wherein the means for adhering the lithographically-printed sheets to the support web comprises an applicator for applying 35 adhesive to the upper surface of the support web upstream of the zone at which the printed sheets are brought into contact with the support web, and pressure means located downstream of said zone for urging the printed sheets against the support web. 5

10. Apparatus according to Claim 7 or 8, wherein the means for adhering the lithographically-printed sheets to the support web comprises an applicator for applying adhesive to the rear face of each of the said sheets 10 upstream of the zone at which the printed sheets are brought into contact with the support web, and pressure means located downstream of said zone for urging the printed sheets against the support web. 15

11. Apparatus according to Claim 7 or 8, wherein the means for adhering the lithographically-printed sheets to the support web comprises coating means for applying a heat-sealable lacquer either to the upper surface of the support web or to the rear face of each label , said 20 coating means being located upstream of the zone at which the printed sheets are brought into contact with the support web, and heated pressure means located downstream of said zone for urging the printed sheets against the support web and curing the heat-sealable lacquer. 25

12. Apparatus according to Claim IT, wherein the heated pressure means comprises one or more pairs of heated rollers. 30

13. Apparatus according to any one of Claims 7 to 12, wherein the transfer means includes rotary indexable arms carrying vacuum-actuated suction pads for holding and releasing the printed sheets to be transferred from the stack of sheets to the support web. 15 -

14. Apparatus according to any one of Claims 7 to 12, wherein the transfer means comprises a carriage which can reciprocably travel from a position above the stack of printed sheets to a position above the support web, the 5 carriage being provided with vacuum-actuated suction pads for gripping a printed sheet and a centrally located solenoid-controlled rod which is arranged to urge a printed sheet downwardly onto the support web when the sheet is released from the said suction pads.

15. Apparatus according to any one of Clams 7 to 12. wherein the transfer means comprises a stream feeder for transferring printed sheets from a stack of sheets to the support web. 10