METHOD AND APPARATUS FOR THE SEPARATION OF SCRAP FILM FROM ADHESIVE LABELS

Abstract: Method and relative apparatus for the separation of scraps from a dinked sheet (1) of adhesive film (3) on a support film (2). The method consists in the placement on a suction surface (7) of a template (8) having a form (A) corresponding to the negative of the scrap (4) to be removed, the placement of the sheet (1) on the suction surface (7), the pressing of said sheet (1) against said suction surface along a line (10) near the external border of the scrap and the application of opposing forces in correspondence with said line respectively to the support film and to the adhesive film, an finally moving the support (2) away from the scrap (4) which adheres to the surface. The apparatus has a suction plane (7) with a line of independent suction points (11). A mobile body (22) is provided rolling on the surface (7) having a suction mouth (14) suited to come into coincidence with said line (10).

Description: TITLE METHOD AND APPARATUS FOR THE SEPARATION OF SCRAP FILM FROM ADHESIVE LABELS. DESCRIPTION Field of the invention . The present invention relates to an method for the separation of scrap film from a dinked sheet of adhesive film on a support film, in particular for the production of adhesive labels. The present invention relates furthermore to an apparatus for carrying out said method. Description of the prior art The preparation of adhesive labels on an industrial level is currently possible only in those cases in which it is not necessary, during the preparation of the same, to remove the portion of scrap adhesive film from the portion of adhesive film that is to constitute the "design" or writing of the label. In practice, labels produced on an industrial scale are made only in cases in which the removal of the scrap film is to be carried out by the final user, or when the scrap film is removed during the dinking step, i.e. cut by means of a dinking die, or hollow punch, together with the silicone coated support paper on which the adhesive film is applied) . The demand by final users for more elaborate adhesive labels, with designs or writing having complex borders, continues to grow. However, the removal of the scrap film from elaborate labels by the final user requires great attention and, therefore, considerable time. To simplify application at the time of use, labels exist in which the scrap film is removed manually by the - 2 - producer after dinking and a transparent adhesive film, known as application tape, having an adhesive strength that is inferior to the adhesive strength which the film exerts on the final application surface, is placed on the remaining adhesive film. This type of label, however, is currently very costly, not so much for the presence of the application tape as for the cost of the manual labour required in separating the scrap film from the sheet composed by the dinked adhesive film and the silicone coated support paper. In an effort to resolve this problem, an apparatus, described in patent application FI/91/A/000086 in the name of the same applicant, has been constructed for the automatic removal of the scrap film of dinked adhesive labels. The described apparatus comprises two suction surfaces, at least one of which is cylindrical, which have relative rolling movement. On one of the suction surfaces a template is present to block the suction of the portion corresponding to the form of the design or writing of the label. The dinked sheet is passed between the two suction surfaces so that the writing or design coincide with the template. Therefore, as the sheet passes, the scrap film detaches from the silicone coated support film and adheres to the suction surface on which the template is present. At the same time, the silicone coated support film adheres to the other suction surface without the portions of adhesive film which constitute the design or writing of the label detaching from it. This is because the template prevents a force of detachment from working on the label. This apparatus is, however, subject to inconveniences resulting from the fact that the suction surfaces, even when exerting the maximum force, are not able to overcome the adhesion between the adhesive film - 3 - and the silicone coated support paper. In fact, the forces of detachment are directed at a right angle to the surface of the scrap film and to the silicone coated support and, therefore, when trying to separate them, a "suction cup effect" occurs which can only be overcome with extremely strong forces. Furthermore, because of the less than perfect hold between the suction surfaces and the films to be separated, due mainly to the elasticity of the silicone coated support paper, very strong suction strength would be necessary to be able to exercise in any case the maximum force. Summary of the invention A first object of the present invention is to provide a method for the separation of scrap film from a dinked sheet of adhesive film on a support film, in particular for the production of adhesive labels, which is able to overcome the above-mentioned inconveniences, allowing for automation of the scrap removal step during preparation of said labels. A second object of the present invention it to provide an apparatus to carry out the above-mentioned method. The first object is accomplished by the method according to the invention which is characterized by the fact that it comprises the steps of: - placement on a suction surface of a template having a form corresponding to the negative of the scrap film to be removed; - placement of the dinked sheet on the suction surface with the nonadhesive face of the adhesive film in contact with the template and with the scrap film to be removed coinciding with the negative of the template, so that only the scrap film is pulled away by the suction surface; pressing against said suction surface of the adhesive film and the support film, which are still in contact with one another along a line coinciding with a portion of external border of the scrap film; - application of opposing forces in correspondence with said line respectively to the support film and the adhesive film; - pulling of the support film starting from said line and moving away from the scrap film which adheres to the suction surface, the support film carrying with it only the portions of adhesive film which constitute the design or writing of the label; removal of the scrap film from the suction surface. Preferably, during the dinking step the execution of a plurality of light punchings distributed on the portions of adhesive film which constitute the scrap film is carried out. The second object is accomplished by the apparatus according to the invention the novel features of which are that, along at least one line of the suction surface, suction points are provided which are independent from the remaining part of the surface and that a body is provided which is mobile with respect to said surface and has a suction mouth suited to bring it into correspondence with said line. Means for drawing the scrap film from the suction surface, means for drawing the sheet deprived of the scrap film from the mobile body, and command means of the suction in correspondence with said surface, said line and said mouth are advantageously provided. According to preferred embodiments, the mobile body rollingly engages on said suction surface and is substantially cylindrical having a suction mouth extending along one of its generatrices. In correspondence with said mouth, gripping means of the support film are provided auxiliary to the suction force exercised by the mouth itself. Brief description of the drawings Further characteristics and advantages of the method and apparatus for the separation of scrap film from a dinked sheet of adhesive film on a support film according to the present invention will become apparent in the description which follows of one of their possible embodiments, given as an example and not limitative, with reference to the attached drawings in which: - figure 1 shows a top plan view of a label prepared for scrap removal with the method according to the invention; - figures 2 and 3 show a longitudinal sectional view of two successive steps of the method according to the invention; - figure 4 shows a simplified top plan view of the step of figure 3; - figure 5 shows a longitudinal sectional view of an example of a punching step during the dinking of the label from which the scrap is to be removed; - figure 6 shows a longitudinal sectional view of an example of a variation of embodiment of the steps of figures 2 and 3; - figure 7 shows a perspective view of an apparatus according to the present invention; - figures 8 and 9 show a lateral elevation view of the apparatus of figure 7 in two successive operative steps; - figures 10 and 11 show respectively a partial longitudinal sectional view and a partial transversal sectional view of the apparatus of figure 7 in correspondence with the suction mouth and detachment of the scrap from the silicone coated support; figure 12 shows a perspective view of a bush forming the suction mouths of figures 10 and 11; - figure 13 shows the auxiliary means for gripping the label according to a variation of the embodiment of the apparatus of figure 10. DP.gcri on of the preferred embodiment With reference to figure 1, an adhesive label forming a design or writing, indicated for the sake of simplification with the letter A, is obtained starting with a sheet 1 comprising a silicon coated support 2 on which is applied an adhesive film 3 which has been dinked according to a cut which separates it into two portions: label A and scrap 4. In order to be able to automatically separate scrap 4 from support 2, so that label A adheres to the latter and scrap 4 can be cleanly removed, it is possible to proceed following the method according to the invention described below. In a first step, during the dinking, it is preferable to execute a plurality of light punchings 5 distributed on the portions of adhesive film 3 which make up scrap 4. Said punching fulfils the purpose of allowing small quantities of air to penetrate between scrap 4 and support 2 in order to considerably reduce the suction cup effect which would be created in the case of their detachment since two opposing forces would be exercised in directions orthogonal to them. Preferably, the punchings are carried out on scrap 4 in proximity to the dinked lines in order to facilitate the entry of air at the time of detachment of support 2 and the portion of film 3 which forms scrap 4. An example of how to form punchings 5 directly during the dinking of sheet 1 is shown in figure 5. The knife 6 of the hollow punch is flanked by a punch 6a which punches the sheet from the side of scrap 4 simultaneously to the cutting of adhesive film 3 by the knife 6 itself. Punchings 5, besides being substantially in the form of a round point as shown in figure 1, can also be elongated to the form of a rectilinear or curvilinear segment. Subsequently, as shown in figures 2 and 3, on a suction surface 7, it is necessary to place a template 8 of a form corresponding to the negative of the scrap 4 to be removed or, in other words, having a form identical to the design or writing of the label, in this case the letter A. Template 8 has, therefore, the function of closing suction holes 9 of surface 7 in an area having a form and position corresponding to the negative of scrap 4 (in this case letter A), when sheet 1 rests there. Sheet 1, therefore, is placed on suction surface 7 with the nonadhesive side 3a of the film in contact with template 8 and scrap 4 to be removed coinciding with the negative 8a of template 8. In this way only scrap 4 is pulled away by suction surface 7, since template 8 has closed punchings 9 corresponding to the position and the form of the negative of scrap 4. Before beginning the detachment of support 2 from scrap 4, it is necessary to press them against suction surface 7, along a line 10, in order to facilitate the suction grip. It is advantageous for scrap 4 and support 2, while still in contact, to be pressed in correspondence with the external border 10a of scrap 4 itself, so that detachment along said line can be begun facilitated by the presence of a small quantity of air penetrating between the support and adhesive films through punchings 5. The detachment occurs, in fact, by applying opposing forces 12 and 13 (fig. 3) , in correspondence with line 10, respectively to support film 2 and the portion of adhesive - 8 - film 3 constituting scrap 4. Force 12 can be exercised by a suction mouth 14 which produces a suction force 12a and is subjected to a force 12b having the same direction and pulling away from scrap 4 which adheres to surface 7 with adhesive face 3b turned in the opposite direction of surface 7. Support 2 is dragged away by mouth 14 carrying with it only the portions of adhesive film 3 which constitute the design or writing of the labels, in this case the letter A. As shown in figure 4, where, for the sake of simplicity, suction mouth 14 has not been illustrated, template 8 coincides exactly with the negative 4a of scrap 4 or, in other words, the space left empty by the letter A which adheres to support 2. Once separation has been completed, support 2 with label A still adhering to it is placed aside in order to apply an application tape onto it which completes the preparation of the label making it ready for the user. In the meantime, scrap 4 is removed from the suction surface to allow for scrap detachment from a subsequent dinked sheet. An advantageous system for preparing template 8 is to completely dink a sheet 1 so that the cut extends also to silicon coated support 2 (e.g. dinking two superimposed sheets 1) . Then, removing silicone coated support 2 only in correspondence with the writing or design A, sheet 1 is placed with adhesive side 3b facing suction surface 7 and aligned with the position which sheet 1 must assume to have the scrap removed. Once writing or design A has adhered to surface 7, scrap 4, which was not able to adhere to it because of the presence of silicone coated support 2 having a form identical to it, is removed. According to a variation of the method according to the invention (figure 6) , mouth 14 can be mounted on a cylinder 22 which rolls on sheet 1 and on which a further - 9 - template 4b, having a form identical to scrap 4, is applied. In this way, template 4b presses against support 2 bending it in correspondence with the lines of the dinking on the side of the scrap and further facilitating the entry of air between the latter and support 2. With respect to the known techniques of scrap removal, possible only manually, the method according to the invention can be automated since all the above- mentioned steps can be carried out by mechanical means. With respect to the automatic scrap removal method carried out by means of the known apparatus described in the introduction, according to the present invention it is possible to eliminate the inconveniences of having to exercise strong suction forces to overcome the strong adhesion between the silicone coated support and the adhesive film caused by the total absence of air between them and the loss of air to which the suction surfaces are subjected. With reference to figures 7 and 8, in fact, an apparatus 21 according to the invention is suited to separate scraps 4 from a dinked sheet 1 of adhesive film on a support film 2, in particular for the production of adhesive labels. Apparatus 21 comprises a flat suction surface on which a template 8 is applicable corresponding to the negative of scrap 4 (see figures 1 to 6) and, therefore, having a form and position coinciding with the writing or design of the label which, in this example, is the letter A. According to the invention, along a line 10 of suction surface 7, independent suction points 11 are provided (see also figures 10 and 11) against which dinked sheet 1, ready for scrap removal, can be pressed by a mobile cylindrical body 22 comprising a suction mouth 14 formed by a plurality of holes 14a located along one of its generatrices and communicating with a suction chamber 23. Body 22 rollingly engages on surface 7, via sheet 1, through means which are not shown and can move from the starting position illustrated in figure 8 to the arrival position illustrated in figure 9. With reference to figures 8, 10 and 11, when body 22 is in the starting position, mouth 14 is brought to coincide with line 10 which comprises independent suction points, or holes, 11 communicating with a suction chamber 24. Points 11 are therefore subject to an independent suction with respect to the rest of surface 7. From body 22, in correspondence with mouth 14, needles 25 protrude suited to engage in some of points 11 of surface 7. Apparatus 1 further comprises, as illustrated in figures 7, 8 and 9, a base 19 and means for drawing scrap 4 from suction surface 7 constituted by a mobile plate 26 moving orthogonally to suction surface 7 on a vertical post 27 and suited to bring itself into contact with said surface. In correspondence with the position of arrival at the end of suction surface 7 (fig. 9) , means are provided for drawing sheet 1, with scrap 4 already removed, from mobile body 22 which comprise an arm 28 oscillating from a drawing position (fig. 8) to a releasing position (fig. 9) . At the free end of arm 28 suction cups 29 are provided, and the other end of arm 28 is rotatingly connected to a support 30. The release of the sheets from which the scrap has been removed occurs on a collecting plane 31. The suction in correspondence with surface 7 and mouth 14 occurs respectively through chambers 20 and 24 and through chamber 23. The suction occurs by means of a first pump 32 and a second pump 33. First pump 32 communicates through conduit 34 with chamber 20 located under suction plane 7 with the exception of points 11 located on line 10. Second pump 33 communicates with chambers 23 and 24 respectively through conduits 35 and 36 and with suction cup 29 through a conduit 37. Pumps 32 and 33 comprise valves for the partializing and inversion of the suction flow indicated respectively with 38 and 39 and acting in synchronism with the movement of mobile body 22 with respect to suction surface 7. A valve 40 is also provided which is independent from valve 39 and suited to command the suction at suction cup 29 by pump 33 through conduit 37. To actuate the scrap removal method according to the present invention by means of apparatus 21, it is necessary, as shown in figure 7, to place template 8, in this case consisting in the letter A, on surface 7. While mobile body 22 is still in the arrival position, on template 8, it is necessary to place sheet 1 of figure 1 so that the letter A of the label coincides with template 8 itself. This is easily possible with the aid of adjustable reference guides which are not shown for the sake of simplicity and since they are of a known type, for example the kind found in paper feeding units present in printers and photocopiers. It is necessary for the starting border of sheet 1 to coincide with line 10 of suction surface 7. At this point, as shown - in figures 8, 10 and 11, mobile body 22 moves into starting position pressing with mouth 14 against sheet 1 in order to facilitate the grip by suction and permit needles 25 to penetrate sheet 1 until they engage in corresponding points 11, so that they pass through both silicone coated support 2 and scrap 4. Needles 25 have the function of bringing air between silicone coated support 2 and scrap 4 and of contributing to the grip of support 2 by suction mouth 14, due to the depression existing in chamber 23 which has been put in communication with pump 33 by means of valve 39. Also chamber 24, located under points 11, is depressed for the same reason and, thus, a suction force is exerted on scrap 4 opposite to that acting on silicon coated support 2. These opposing forces make it so that as soon as body 22 begins to roll in the direction of arrow 44, silicone coated support 2 detaches from scrap 4 in correspondence with line 10. As body 22 proceeds in the direction of arrow 44, silicone coated support 2 adheres to it detaching itself more and more from scrap 4 and carrying with it the part of adhesive film 3 which constitutes the letter A, or the writing or design of the label. The label, in fact, thanks to the presence of template 8, is not forced to adhere to surface 7 by the depression created in chamber 20 by pump 32 with whose suction chamber it communicates by way of valve 38. Once the arrival position has been reached, as shown in figure 9, valves 38, 39 and 40 invert cutting off the suction of chambers 20, 23 and 24 while opening the suction of suction cups 29. Consequently, following the oscillation of arm 28, sheets 1, already having had the scrap removed, can be dropped onto collection plate 31. Contemporaneously, plate 26 lowers in the direction of arrow 45 until it touches scrap 4 which adheres to it since its adhesive side 3b is facing upward. As shown, the successively removed scraps 4 form a very compact pile adhering to plate 26, with the consequent considerable practical advantage of reducing the volume of scrap film per unit weight. With reference to figures 10, 11 and 12, each of suction mouths 14 can be advantageously composed of a metallic bush 15 which engages sealed with body 22. A cap 16 screws onto bush 15 and, by closing it, stops both a needle 25, which passes through it, and a pneumatically sealant O-ring 18. The grip of the label on support 2 which must assure its detachment from scrap 4 is, therefore, obtained by the combination of the force of penetration of needles 25, both in support 2 and in scrap 4, and the suction of mouths 14. The detachment is facilitated by the pneumatic seal provided by O-rings 18 and by the further air that has penetrated between support 2 and scrap 4 due to the punchings. The same "suction cup effect" between support 2 and scrap 4 is manifested, even though in a lesser way, also along the edges of the scrap which surround the label . In some critical points such as isolated portions of scrap, said effect could contrast the detachment, and the scrap could be carried away along with the labels. In the case of labels with critical points of this type it is possible to use a variation of embodiment of the invention illustrated in figure 13 as an alternative to the counter- template of figure 6. As can be seen in figure 13, one end 46 of a transparent flexible panel 47 can be fixed to mobile body 22, for example by means of a small magnetic block 49. The other end 48 of flexible panel 47 is anchored by means of screws 50 to suction plane 7 in proximity to its end 7a (on the side of suction cups 29),opposing line 10 of the beginning of scrap removal. Panel 47 can be used as a support for needles 51, which can be for example drawing pins, which punch, besides flexible panel 47 itself, also support 2 and scrap 4 in order to facilitate detachment by air penetration and eliminate the suction cup effect. Needles 51 can be easily positioned immediately after the application of template 8 on suction plane 7, before initiating the scrap removal. In fact, after body 22 has returned to its starting position, flexible panel 47 extends on plane 7 and template 8 remains visible since the flexible panel 47 is transparent. Needles 51 can, therefore, be placed in the critical points of the successive scrap to be removed, making sure they coincide with one of the holes 9 nearest to said points. Advantageously, flexible panel 47 is composed of a known film called Lexan. Sheet 1 which is to have the scrap removed from it with the apparatus according to the invention can be of any reasonable form or dimension. Therefore, in the majority of cases, suction surface 7 will be of a dimension greater than that of sheet 1. Thus, in order to allow for suction on the part of surface 7 itself, it is advantageous to seal its uncovered portions for example by means of adhesive sheets 17 or other equivalent means. The apparatus according to the invention allows, therefore, for the automatic removal of the scrap film of sheet 1 with considerable speed and efficiency, thus allowing the production of adhesive labels of the above- mentioned type to increase to an industrial scale with a considerable reduction of costs. Variations and/or modifications can be brought to the present invention without departing from the scope of the invention itself.

Claims: Ci IMS 1. Method for the separation of scrap film from a dinked sheet of adhesive film on a support film, in particular for the production of adhesive labels, characterized by the fact that it comprises the steps of: - placement on a suction surface of a template having a form corresponding to the negative of said scrap film; - placement of said sheet on said template with the nonadhesive face of said film in contact with said template and with said scrap coinciding with the negative of said template, so that only the scrap film is sucked away by said suction surface; - pressing against said suction surface of said adhesive film and said support film still in contact with one another along a line coinciding with a portion of external border of the scrap film; - application of opposing forces in correspondence with said line respectively to said support film and said adhesive film; - pulling of said support film starting from said line and moving away from said scrap film which adheres to the suction surface, said support film carrying with it only the portions of adhesive film which constitute said labels; - removal of said scrap film from said suction surface. 2. Method according to claim 1, wherein said opposing forces applied respectively to said support film and said adhesive film in correspondence with said line are produced by suction, and the pulling of said film starting from said line is produced by the grip of a moving suction body. 3. Method according to claim 2, wherein said pulling of said support film starting from said line is produced by means of the grip of said moving suction body through suction mouths formed in it and with the aid of punching needles. 4. Method according to the previous claims wherein said mouths are mounted on a cylinder which rolls on said suction surface and on which a counter-template corresponding to said scrap is applied. 5. Method according to the previous claims wherein said template is prepared following the steps of: - complete dinking of one of said sheets so that the cut extends also to said silicone coated support; removal of said silicon coated support only in correspondence with said writing or design; - placement of said sheet with its nonadhesive side facing said suction surface and aligned with the position which said sheet, in preparation to have the scrap removed, must assume; - removal of said scrap along with said remaining silicone coated support so that only said design or writing adheres to said suction surface. 6. Method according to the previous claims wherein during the dinking step a plurality of light punchings are made dispersed on the portions of said adhesive film which make up said scrap film, said punchings being carried out by means of a plurality of punches associated with a hollow punch from the side of said scrap. 7. Apparatus for the separation of scraps from a dinked sheet of adhesive film on a support film, in particular for the production of adhesive labels, comprising a suction surface on which a template is applicable corresponding to the negative of said scrap, characterized in that along at least one line of said suction surface suction points are provided that are independent from the remaining part of the surface itself and that a mobile body is provided moving with respect to said surface having a suction mouth suited to carry it into coincidence with said line. 8. Apparatus according to claim 7 wherein said mobile body rollingly engages on said suction surface, means being provided for drawing said scrap from said suction surface as well as means are provided for drawing said sheet, with the scrap already removed, from said mobile body, in addition to command means of the suction in correspondence with said surface and said mouth. 9. Apparatus according to claims 7 and 8 wherein said mobile body is substantially cylindrical and said mouth extends along one of it generatrices. 10. Apparatus according to claims 7 to 9 wherein, in correspondence with said mouth, means are provided for gripping said support film which are auxiliary to the suction force exercised by said mouth. 11. Apparatus according to claim 10 wherein said mouth comprises a plurality of substantially aligned suction holes, said gripping means comprising needles protruding orthogonally to said body and suited to engage in suction holes provided in said suction surface in correspondence with said line with raised portions. 12. Apparatus according to claim 11 wherein said holes are formed by bushes engaging in said mobile body and on which caps engage which block said needles and an elastic sealing ring. 13. Apparatus according to claims 7 to 12 wherein said suction surfaces comprise a first suction chamber located in correspondence with said line, and a second suction chamber located in correspondence with the remaining part of the surface. 14. Apparatus according to claims 7 to 13 wherein said command means of the suction comprise a first and second pump communicating respectively with said first and second chamber, said first pump communicating also with said suction mouth of said mobile body. 15. Apparatus according to claims 7 to 14 wherein said first and second pumps comprise partialization and inversion valves of the suction flow acting in synchronism with the movement of said mobile body with respect to said suction surface. 16. Apparatus according to claims 7 to 15 wherein said means for drawing said scrap from said suction surface comprise a plate which is orthogonally mobile with respect to said suction surface and suited to come into contact with it when said mobile body has separated said support film from said scrap which adheres to said surface. 17. Apparatus according to claims 7 to 16 wherein said means for drawing said sheet deprived of said scrap from said mobile body comprise suction cup means which enter into contact with said support film in correspondence with said mouth of said mobile body when it has separated said support film from said scrap. 18. Apparatus according to claims 7 to 17 wherein one end of a transparent flexible panel is fixed to said mobile body, the other end 48 of the flexible panel being anchored by means of screws to said suction plane in proximity to the end of the plane opposite said line, with auxiliary needles being fixed to said flexible panel which are suited to penetrate said sheet for the facilitation of the scrap removal. 19. Method and apparatus for the separation of scrap from a dinked sheet of adhesive film on support film, in particular for the production of adhesive labels substantially as described above and illustrated with reference to the attached drawings.

Inventors: LOSI BRUNO, LOSI, BRUNO
Applicants: LOSI BRUNO, LOSI, BRUNO
Application year: 1995
Main classification: B65C9
IPC codes: B26D7, B65C9