Method of producing blocks of self-adhesive labels or the like

Abstract: A method of producing blocks of self-adhesive labels or the like comprises feeding continuously to a cutting device (12, 13; 33, 34) a continuous label stock (10; 30) which on one face has a number of repeated images (11; 31) overlaid by a release coating and on the other face has a pressure-sensitive adhesive coating (16; 32). In the cutting device a succession of sheets (20, 37), each having more than one image, is cut from the stock and the sheets are formed into a stack (21; 38) of superimposed cut sheets, either simultaneously with the cutting or in a subsequent step. Finally, a number of blocks of superimposed labels or the like, each having a single image, are cut from the stack of sheets. Various methods of applying the labels from the blocks to cylindrical or non-cylindrical bodies are given.

Description: The present invention is a method of producing blocks of self-adhesive labels or the like. Self-adhesive labels are widely available in the form of individual labels or as continuous rolls of labels and they have usually been provided adhered to a liner of backing material which is coated to facilitate removal of the label when it is to be used. The separating of label and liner is sometimes a difficult exercise and furthermore the use of a backing material for this purpose is inherently wasteful since it is discarded after separation. In addition, the presence of a liner affects the handling or treatment of the label proper, for example during printing of the label. For these reasons among others, it has been suggested to provide blocks of superimposed self-adhesive labels wherein the backing material is omitted and the front face of each label is coated with a release coating to facilitate separation of successive labels from the block for use. Such blocks or pads of labels are described in Patent Specification GB 2156705 and in European Patent Specification No. 0244265. Blocks of superimposed self-adhesive labels of the foregoing kind are cut directly fro a continuous label stock by means of a hollow die. A separate hollow die is used for each block to be cut. Thus the production capacity of a given cutting station, and in turn of a production line including that cutting station, is limited by the number of hollow dies available. Since the cost of producing label blocks by this method is governed both by the cost of the equipment and by the rate at which the blocks are produced, the number of hollow dies employed is a significant influence on the production cost. French Patent Specification No. 2591535 and corresponding UK Specification No. 2186840 describe a process for the manufacture of pads of "self-sticking" notes of the type which have a re-usable adhesive on a part of the area of one face of the note. The process includes cutting sheets from a continuous web of paper having the re-usable adhesive on one face, stacking the cut sheets and subdividing the stack into a plurality of pads. It is an object of the present invention to provide a method of producing blocks of self-adhesive labels or the like, which method is an improvement of prior methods proposed for this purpose and makes possible the production of the desired blocks at an increased production rate. The method according to the present invention for producing blocks of self-adhesive labels or the like comprises feeding continuously to a cutting device a continuous label stock having a multiplicity of repeated images on a first face thereof overlaid by a release coating and further having a pressure-sensitive adhesive coating on the second face thereof, cutting from areas of the continuous label stock spaced from the side edges thereof a succession of cut sheets each having a plurality of said images thereon, forming a stack of superimposed said cut sheets, and subsequently cutting from a said stack a plurality of blocks of superimposed labels or the like, each said label or the like having a single said image thereon. While, in the foregoing discussion, the invention has been described in the context of the production of labels, the present invention is equally applicable to the production of blocks of self-adhesive products similar to labels. For example, rectangular or other shaped objects may be used for wall decoration in the manner of wallpaper strips or tiles and may be produced in blocks by the process according to the invention. Interlocking cut shapes, for example hexagons or triangles, may be used to provide a continuous decorative design. By way of further example, strips of self-adhesive decorative tape such as are commonly used for packaging purposes and conventionally dispensed from a roll may be produced in block form by the present process. To avoid undue repetition, the description of the present invention hereinafter will be confined to its application to the production of labels. However, it will be readily recognised that such related diverse products as are referred to above may be produced by the same process. The images upon the first face of the continuous label stock may be formed by printing or by photographic reproduction. A multiplicity of repeated such images are applied, with the aim that each of the said images shall form or appear upon a single label. Photographic imaging is a known means of providing very high quality, full colour images very economically for users who require a relatively small number of labels. However this technique is rarely used with conventional self-adhesive labels because of the very high cost of converting the photographic web into a self-adhesive laminate. In the case of the present invention, the use of photographic imaging is more readily acceptable. The continuous label stock may be of paper but non-paper substrates, for example substrates of synthetic polymeric sheet materials, are also suitable. The images on the first face of the continuous label stock are overlaid by a release coating to reduce the adhesion between adjacent superimposed labels and permit their separation without harm to the labels or to the images thereon. Such release coatings are well known and are readily available. The second face of the continuous label stock carries a coating of a pressure-sensitive adhesive. Again, such adhesives for coating labels are well known and are readily available from a range of suppliers. The continuous label stock is fed continuously to a cutting device and is there cut to form a succession of cut sheets, each of which has a plurality of the repeated images on it. The images upon the cut sheets may be repeated in the direction of the length of the stock and/or in a direction across the length of the stock, or in an intermediate direction. A stack of superimposed cut sheets is formed, either simultaneously with the cutting of the sheets from the stock or in a subsequent operation. Thus, for example, particularly with the achievement of high-speed production in mind, the continuous label stock may be fed to a rotary die, by means of which an incomplete cutting is effected whereby each intended sheet is cut along a major proportion of its circumference but is left joined to the continuous web at a small number of positions around its circumference. In this way, the intended sheets are readily conveyed to a station whereat the sheets are separated from the web to form a superimposed stack of sheets. This subsequent separating and stacking of the sheets may readily and advantageously be carried out by means of a shear cutting device. By oscillating the movement of the shear cutting device, or oscillating that of feed-in and feed-out rollers associated with the device, it is possible to maintain the continuous label stock in continuous forward movement, so that high production speeds can be achieved. As an alternative, the cutting and stacking of the sheets may be carried out simultaneously in a single operation. For this purpose, the continuous label stock may be fed continuously to a die set comprising cooperating male and female dies. As each sheet is cut from the continuous web it is superimposed upon previously cut sheets within the hollow female die and forms a stack which may be withdrawn from the rear of the die. Preferably, the surface surrounding the cutting area of the female die is modified to render it non-sticking, for example by roughening that surface or by applying to it a non-stick coating such as of polytetrafluoroethylene. In addition, it is preferred to dispose an apertured panel between the continuous stock and the male die such that, when the male die is withdrawn through the aperture after each cutting stroke, adhesion of the web to the die is prevented. It is also generally advantageous to arrange that the adhesive coating is absent from the web in the region of the periphery of the intended cut sheets. In this way, the adhesive cannot impede the cutting operation. Since the peripheral areas of the sheets may be discarded in the subsequent cutting of the label blocks from the sheet stack, adhesion of the labels in use is unaffected. The final cutting of the blocks of superimposed self-adhesive labels from the stacks of cut sheets may be carried out manually or automatically or semi-automatically. For example, the stacks may be cut by means of a guillotine or a die cutter may be employed for this purpose. The blocks of labels which are produced by the process of the present invention will normally be straight-sided vertical stacks. In order for each individual label to be dispensed from the block, particularly where the labels are to be applied mechanically to containers or the like, it is desirable that the labels be of relatively stiff material. However, according to one aspect of the invention, the blocks may be modified after production by displacing adjacent labels from vertical superimposition. This may then allow the labels to be applied more readily directly from the block, with the result that less stiff materials may be used. The displacing may, for example, be by an amount not exceeding 45 degrees from the vertical, preferably between 5 and 25 degrees. The displacing may readily be carried out mechanically, for example by securing one or more blocks of labels in a clamp and applying a shear force to the top surface of the clamp. The invention will now be further described and illustrated with reference to the accompanying drawings, wherein: Fig. 1 is a diagrammatic representation of a first preferred method of forming a stack of superimposed sheets according to the present invention; Fig. 2 is a diagrammatic representation of a second preferred method of forming a stack of superimposed sheets according to the invention; and Fig. 3 and 4 respectively illustrate diagrammatically the advantage of modifying the label blocks produced by the method according to the invention . As illustrated in Fig. 1, a continuous label stock in the form of a web 10, which has been printed with a multiplicity of repeated images 11, is fed continuously at speed into the nip between an engraved cutting roller 12 and a backing roller 13. The cutting roller 12 has knife edges 14 on its surface and the rollers together cut the web in register with the images 11 to form incompletely-cut sheets 15 each bearing several of the images 11. The web 10 is so fed to the rollers 12, 13 that the adhesive surface 16 of the web contacts the knife edges 14 but not the surface of the roller 12. The cuts around the periphery of the sheets 15 are discontinuous so that small bridges 17 are left connecting the sheets 15 to the web, to enable the sheets 15 to be carried to the next station, which is a stacking device. The stacking device comprises two cooperating parts 18 and 19 which together shear-cut the bridges 17 and places each cut sheet 20 upon the previously-cut sheets to form a stack 21. If a continuous motion of the web 10 is required for high-speed operation then the stacking device is given an oscillating movement such that the stacking unit is moving in the same direction as the web, and at the same speed, during the pressing-out operation. Alternatively feed-in and feed-out rollers can be employed with an oscillating movement such that the continuously moving web is actually stationary between the top and bottom parts 18, 19 during the pressing-out operation. The stack 21 of cut sheets 20 is removed from the underside of the stacking device part 19 and cut vertically to form a number of blocks of labels, each bearing one image 11. The upper surface 22 of the part 19 of the stacking device may be coated with a non-stick material to prevent adhesion of the web 10 to that surface. Referring now to Fig. 2, the illustrated continuous web 30, carrying groups of repeated printed or photographic images 31 on its upper surface and overlaid on that surface with a release coating, has a coating 32 of pressure-sensitive adhesive on its lower surface. The web 30 is conveyed to and from a die set by feed-in and feed-out rollers (not shown) operated with an oscillating motion, so that the web, while fed continuously from its source, is intermittently stationary between the dies of the die set. An advantage of this form of cutter as contrasted with that of Fig. 1 is that the action of the die set is a shearing action and thus the cutting edges are not blunted, or the cutting base worn, by repeated mutual contact. The die set comprises a male die 33 and a female die 34, the upper surface 35 of the latter being coated with a non-stick material to avoid the web adhering to the female die. Disposed between the web 30 and the male die 33 is an apertured plate 36, through which the male die passes during the cutting stroke. The function of the plate 36 is to assist disengagement of the web from the male die as the latter is withdrawn after cutting. After each cutting stroke, the web is advanced ready for the next stroke. Sheets 37 are cut from the web 30 by the die set 33, 34 in register with the repeat pattern of the images 31, such that each sheet 37 carries a number of images (ten in the illustrated example). The cut sheets form a stack 38, which may be withdrawn from below the female die. Subsequent cutting of the stack 38 gives, in the illustrated case, ten blocks of labels, each carrying a single image 31. Figure 3 illustrates diagrammatically a block 43 of labels 40, each having a release coating 41 and an adhesive coating 42. The block 43 has been modified by displacing each label 40 a short lateral distance from the one below it. Thus the block is inclined by the angle identified by the numeral 44. As a result, when a container 45 is rolled across the uppermost label 40 in the block, the first label is more readily detached from the remaining labels in the block. An alternative way in which a block 50 of labels 51 may advantageously be modified is illustrated diagrammatically in Fig. 4, wherein the labels 51 are each given a curve with the adhesive surface 52 on the convex face of the curved label. The curve can be introduced mechanically or by applying moisture to one side of the paper web. Again pick-up of the top label in the block by a rotating container 53 is assisted as a result of the modification of the block.

Claims: A method of producing blocks of self-adhesive labels or the like by cutting sheets from a continuous web of material having a pressure-sensitive adhesive on one face thereof, forming a stack of said cut sheets and subdividing each stack into said blocks, said method comprising the steps of feeding continuously to a cutting device (12, 13; 33, 34) a continuous label stock (10; 30) having a multiplicity of repeated images (11; 31) on a first face thereof overlaid by a release coating and further having said pressure-sensitive adhesive coating (16; 32) on the second face thereof, cutting from areas of the continuous label stock spaced from the side edges thereof a succession of cut sheets (20; 37) each having a plurality of said images thereon, forming said stack (21; 38) of superimposed said cut sheets, and subsequently cutting from said stack a plurality of said blocks of superimposed labels or the like, each said label or the like having a single said image thereon. A method according to claim 1, wherein the cutting of the sheets from the continuous label stock and the forming of a stack of superimposed cut sheets are performed in successive separate operations. A method according to claim 2, wherein the cutting of the sheets from the continuous label stock comprises an incomplete cutting by means of a rotary die (12, 13) and the incompletely cut sheets (15) are then separated from the stock and simultaneously stacked, by means of a shear cutting device (18, 19). A method according to claim 1, wherein the cutting of the sheets from the continuous label stock and the forming of a stack of superimposed cut sheets are performed in a single operation. A method according to claim 4, wherein said single cutting and stacking operation is performed by means of a die set (33, 34). A method according to claim 5, wherein the surface (35) surrounding the cutting area of the female die (34) of said die set is modified to render that surface non-sticking. A method according to claim 5 or claim 6, wherein an apertured panel (36) is disposed between the continuous label stock and the male die (33) of said die set, through which aperture the male die passes during the cutting. A method according to any of the preceding claims, wherein the continuous label stock has the pressure-sensitive adhesive coating on only part of the area of its second face such that said adhesive is absent in the region of cutting of sheets from said stock. A method according to any of the preceding claims, wherein the cutting of a plurality of blocks of superimposed labels or the like from a stack of superimposed cut sheets is carried out with a guillotine or die cutter. A method according to any of the preceding claims, wherein the resulting blocks of superimposed labels or the like are subsequently modified (Figs. 3; 4) by displacing adjacent labels from vertical superimposition.

Inventors: LACY ROBERT MICHAEL, LACY, ROBERT MICHAEL
Applicants: LACY ROBERT M, LACY, ROBERT MICHAEL
Application year: 1988
Main classification: B31D1
IPC codes: B26D7, B31D1