Method and system of removing a printing film

Abstract

A method of removing a film from a hollow body (3), around which a film (2) has been previously heat-shrunk and wherein the hollow body (3) extends along a longitudinal axis (A), provides for making two slits (14) in the film (2) at one end of the hollow body (3) so as to define two flaps (15) arranged on opposite sides of the body (3) with respect to the longitudinal axis (A); gripping the flaps (15) by respective gripping members (18); and simultaneously advancing the gripping members (18) and the respective flaps (15) in two opposite directions with respect to the longitudinal axis (A) so as to tear the film (2).

Description

[0001] "METHOD AND SYSTEM OF REMOVING A PRINTING FILM"

[0002] Cross-Reference to Related Applications

[0003] This Patent Appl ication claims priority from Italian Patent Application No . 102024000014668 filed on June 26 , 2024 , the entire disclosure of which is incorporated herein by reference .

[0004] Technical Field

[0005] The present invention relates to a method of removing a printing film, in particular a heat-shrinkable film for printing the outer surfaces of hollow containers such as bottles , vials and vases made of glass , ceramic or similar materials .

[0006] State of the Art

[0007] Equipment and procedures for producing decorations by means of a heat trans fer using inks , in particular via sublimation printing, are known .

[0008] In this field, there is a growing demand for high- quality sublimation printing that is able to provide a high image definition and precision in the af fixing of decorations or writings with respect to speci fic reference points of the hollow body .

[0009] In particular, document WO 2021 / 260613 Al teaches how to af fix decorations to vitreous hollow bodies and the like , such as bottles or vials , by means of a sublimation printing process with high quality levels in terms of image definition and image-af fixing precision . The process described in such patent document provides for producing a sleeve , which has an irregular inner face , is obtained from a sheet of film made of a thermoplastic material , generally PET or PETG, wrapped to form a cylinder and sealed on the flaps with adhesive or solvent of the polymer by means of a tubing machine , and which bears a design along its irregular inner face . The design is produced directly on the film with an ink that is intended to be trans ferred onto the hol low body to be decorated .

[0010] The process provides for arranging the sleeve around the hollow body, applying heat to the sleeve so as to determine its heat-shrinking and adhesion to the hollow body, applying heat to the sleeve and hollow body at a sublimation temperature of the ink in order to sublimate the ink particles and produce the trans fer of the design onto the hollow body, and simultaneously extracting the excess gas produced in the sublimation through a network of microchannels that extend between the heat-shrunk sleeve and the hollow body . The micro-channels between the hollow body and the heat-shrunk sleeve are formed thanks to the fact that the sleeve has a rough inner face prearranged for forming the micro-channels once the sleeve has been heat-shrunk to form a film that adheres to the hollow body . The process described in WO 2021 / 260613 Al results to be particularly satis factory with regard to the qualitative aspects , however , one of the problems encountered in sublimation printing is that of combining a high qualitative level with an ef f icient industrial isation of the production process so as to reduce the production costs . A drawback that has been encountered in the known processes involves the removal of the film upon completion of the trans fer of the sublimation inks .

[0011] Subject-Matter of the Invention

[0012] An obj ect of the present invention is to provide a method of removing a film from a hollow body, around which the film has been previously heat- shrunk, which is easy and cost-ef fective to implement from the industrial point of view .

[0013] In accordance with the present invention, a method of removing a printing film from a hollow body, around which a film has been previously heat-shrunk and wherein the hollow body extends along a longitudinal axis is provided, the method comprising :

[0014] - making two slits in the film at one end of the hollow body so as to define two flaps arranged on opposite sides of the hollow body with respect to the longitudinal axis ;

[0015] - gripping the f laps by respective gripping members ; and - simultaneously advancing the gripping members and the respective flaps in two opposite directions with respect to the longitudinal axis so as to tear the film .

[0016] In this manner it is possible to quickly free the hollow body of the film .

[0017] In particular, the method provides for simultaneously advancing the gripping members and the respective f laps along a direction paral lel to the longitudinal axis so as to follow the tear area as it progresses along the axis of the hollow body .

[0018] In particular, the slits are parallel to the longitudinal axis so as to define an initiation in the tearing traj ectory .

[0019] In accordance with the present invention, the slits are made at a fitting, which is integral with said hollow body, and is partially wrapped by the film together with the respective hollow body .

[0020] In fact , the fitting is used in the sublimation process both to support the hollow body and to evacuate gases produced in the sublimation process between the film and the hollow body . Making the slits at the fitting avoids damaging any decorations af fixed to the hollow body with the tools used to make the slits .

[0021] In order to automate the operations of the film, the method provides for advancing the hollow body and the respective film along a given feed path through a cutting station to make said flaps and a removal station to remove said film .

[0022] The method provides for rotating said hollow body and the relative film about the longitudinal axis by 90 ° in a rotation station between the cutting station and the removal station along the feed path in order to arrange the flaps so that they can be easily gripped by the respective gripping members .

[0023] A further obj ect of the present invention is to provide a removal system for removing a fi lm from a hollow body which is simple and ef ficient .

[0024] In accordance with the present invention, a removal system is provided for removing a printing film from a hollow body, around which the film has been previously heat-shrunk and wherein the hollow body extends along a longitudinal axis , the method comprising :

[0025] - at least one cutting device configured to make two slits in the film at one end of the hollow body so as to define two flaps arranged on opposite sides of the hollow body with respect to the longitudinal axis ;

[0026] - two gripping members to grip the flaps ; and

[0027] - an actuator assembly configured to simultaneously advance the gripping members and said flaps integral with the respective gripping members in two opposite directions with respect to the longitudinal axis so as to tear the film .

[0028] In this manner , the film is removed with extreme easiness from the hollow body .

[0029] In particular, the actuator assembly comprises two linear actuators , which support at their free ends the respective gripping members and are configured to simultaneously advance the gripping members and the respective flaps along a direction parallel to the longitudinal axis .

[0030] In this manner, two tearing traj ectories are originated from the slits which allow completely freeing the hollow body of the film .

[0031] From a constructive point of view, the actuator assembly comprises a guideway arranged above the conveyor transversely to the feed path and two carriages , which are selectively movable along the guideway by means of respective actuators and are configured to support said linear actuators .

[0032] In particular, the system comprises two cutting devices for making the slits in the film at two opposite end sections of the film so as to define said flaps .

[0033] In this manner, the slits are made simultaneously .

[0034] In accordance with the present invention, each cutting device is configured to emit a respective laser beam in order to make the slit at a fitting integral with said hollow body, said fitting being partially wrapped in the film together with the respective hollow body .

[0035] In this manner, damage to the hollow body and its decoration is avoided .

[0036] In particular, the system comprises a conveyor configured to advance said hollow body and the respective film along a given feed path through a cutting station for making the slits and said relative flaps and a removal station 10 for removing said film .

[0037] In this manner, the operations can be easily industrialised .

[0038] Furthermore , the conveyor comprises a plurality of support devices configured to support said hollow bodies with their longitudinal axes oriented in a vertical direction .

[0039] The support devices are configured to support the hollow bodies according to a preferred orientation for performing the operations .

[0040] In accordance with the present invention, the conveyor comprises at least one rotation device for rotating each support device and the respective hollow body around the longitudinal axis by 90 ° in a rotation station arranged between the cutting station and the removal station so as to arrange the flaps in a position where they can be easily gripped by the gripping members . List of the Figures

[0041] The present invention will be described with reference to the attached figures depicting an embodiment thereof , wherein :

[0042] - Figure 1 is a plan view, with parts removed for clarity, of a removal system for removing a film adhering to a hollow body following a heat-shrinking process ;

[0043] - Figure 2 is a lateral elevation view, with parts removed for clarity, of the removal system for removing a film;

[0044] - Figures 3 , 4 and 5 are front elevation views , with parts in section and parts removed for clarity, of a detail of the removal system for removing the film in respective operating steps ; and

[0045] - Figures 6 and 7 are views , with parts in section and parts removed for clarity and on an enlarged scale , of respective details of the system obj ect of the present invention .

[0046] Preferred Embodiment of the Invention

[0047] In Figures 1 and 2 , reference numeral 1 indicates , as a whole , a removal system for removing a film 2 adhering to a hollow body 3 , in this case a bottle , following a heatshrinking process .

[0048] The system 1 comprises a conveyor 4 provided with an actuator 5 configured to advance a base element 6 and a plurality of support devices 7 along a feed path P, along which a cutting station 8 , a rotation station 9 and a removal station 10 are arranged in sequence .

[0049] Each support device 7 is configured to support a respective hollow body 3 by means of a fitting 11 along a longitudinal axis A, as better illustrated in the enlargement of Figure 6 . The hollow body 3 and the respective fitting 11 are wrapped in the film 2 upstream of the removal station 10 . In this case , the film 2 forms a sealed fold 12 at the end of the hollow body 3 opposite the fitting 11 .

[0050] Each support device 7 is mounted so as to be rotatable with respect to the base element 6 and is configured to suck gas into the gap formed between the hollow body 3 and the film 2 .

[0051] The system 1 comprises two cutting devices 13 arranged on opposite sides of the conveyor 4 and configured to make respective slits 14 along the film 2 parallel to the longitudinal axis A at the fitting 11 so as to define two opposite flaps 15 , as better illustrated in Figure 3 . In this case , each cutting device 12 is a laser-beam emitter that is movable in a direction parallel to the longitudinal axis A.

[0052] In the rotation station 9 , the support device 7 is rotated by 90 ° about the longitudinal axis so as to arrange the flaps 15 at the long opposite sides of the conveyor 4 . The rotation of the support device 7 is obtained through the engagement of the hollow body 3 with two rotation devices 16 which impart on the hollow body 3 the rotation around the axis A.

[0053] The system 1 comprises a removal device 17 configured to grip the flaps 1 and tear the f ilm 2 so as to remove it , as better illustrated in Figure 3 .

[0054] With reference to Figure 3 , the removal device 17 is arranged in the removal station 10 and comprises two gripping members 18 , and a guideway 19 , two carriages 20 that are movable along the guideway 19 and two linear actuators 21 , each of which is connected to a respective carriage 20 and a respective gripping member 18 .

[0055] With reference to Figure 7 , each gripping member 18 comprises a gripper 22 provided with two j aws 23 and a suction port 24 , which is arranged between the two aws 23 and is configured to adhere to a respective flap 15 and detach the flap 15 from the fitting 11 to an extent that it can be clamped between the two j aws 23 ( Figure 3 ) .

[0056] With reference to Figure 3 , the guideway 19 is substantially hori zontal and is arranged above the conveyor 4 transversely to the feed path P . The carriages 20 are selectively movable along the guideway 19 by means of further actuators 25 and are configured to move the respective gripping members 18 away from and close to the conveyor 4 . Each linear actuator 21 is coupled to a respective carriage 20 in a selectively adj ustable manner so that the linear actuator 21 can be given a specific inclination with respect to the guideway 19 .

[0057] Thanks to the inclination with respect to the guideway 19 , the linear actuators 21 are able to move the gripping members 18 in respective directions comprising components parallel to the guideway 19 and parallel to the longitudinal axis A.

[0058] In use , once the sublimation phase is complete , the hollow bodies 3 coated by the fi lms 2 are advanced by the conveyor 4 along the feed path P in a stepped manner through the cutting station 8 , the rotation station 9 and the removal station 10 , as illustrated in Figures 1 and 2 .

[0059] The film 2 is made of a material selected among PET , PETG, PVC, PE and PP . In particular, the film 2 is made using a strati form material with a base layer made of anisotropic heat-shrinkable PET and PETG, i . e . shrinkable in one direction only .

[0060] The cutting station 8 , the rotation station 9 and the removal station 10 are arranged directly downstream of the sublimation station (not illustrated in the attached figures ) in such a manner that the film 2 has not yet cooled, in this case has a temperature above 90 ° C, so that it is still mainly in a plastic phase . In the cutting station 8 , the slits 14 are made in order to define the flaps 15 , which are rotated in the rotation station 9 so as to face the gripping members 18 in the removal station 10 .

[0061] In the removal station 10 , the suction ports detach the flaps 15 , which are gripped by the respective grippers 22 , as illustrated in Figure 3 .

[0062] With reference to Figures 4 and 5 , the actuators 25 and the linear actuators 21 move the gripping members 18 away from the longitudinal axis A, dragging the respective flaps 15 with them, and the film 2 tears along two tearing traj ectories that are substantially parallel to the longitudinal axis A and originate from the respective slits 14 until the hollow body 3 has been completely freed .

[0063] EXAMPLE

[0064] The Applicant carried out tear tests with a film derived from a laminated sheet which uses a base layer made of 78 % PETHSGB heat-shrinkable material with a thickness of 40 microns at di f ferent temperatures .

[0065] The tests performed provided results that are summarised in the following .

[0066] In the range between 150 ° C and 120 ° C, the tearing of the film progresses with extreme easiness along the vertical lines until the film has been completely removed .

[0067] In the range between 120 ° C and 90 ° C, the tearing of the film is irregular and complex to manage because crystallisation bonds begin to form .

[0068] Below 90 ° C, the tearing of the film is not possible due to the crystallisation / cross-linking of the film, which determines the fragmentation thereof .

[0069] The general principle consists in the fact that , irrespective of the type of material used, the correct execution of the tear occurs when the film is in the plastic phase and is far from a vitreous phase .

[0070] Finally, it is evident that the present invention comprises further variations of the described embodiments included within the scope of protection of the appended claims .

[0071] For example , the suction ports are connected to a suction system not illustrated in the attached figures .

[0072] The conveyor is advanced continuously and the cutting devices and the removal device are configured to follow the conveyor along a section of the feed path and to return to the initial position . It is obvious that the cutting devices can di f fer from those described, in particular in one embodiment they can comprise blades , in particular rotating blades .

Claims

CLAIMS1. A method of removing a printing film from a hollow body (3) , around which a film (2) has been previously heat- shrunk and wherein the hollow body (3) extends along a longitudinal axis (A) , the method comprising:- making two slits (14) in the film (2) at one end of the hollow body (3) so as to define two flaps (15) arranged on opposite sides of the hollow body (3) with respect to the longitudinal axis (A) ;- gripping the flaps (15) by respective gripping members (18) ; and- simultaneously advancing the gripping members (18) and the respective flaps (15) in two opposite directions with respect to the longitudinal axis (A) so as to tear the film (2) .

2. The method as claimed in claim 1 and comprising simultaneously advancing the gripping members (18) and the respective flaps (15) along a direction parallel to the longitudinal axis (A) .

3. The method as claimed in claim 1 or 2, wherein the slits (14) are parallel to the longitudinal axis (A) .

4. The method as claimed in any one of the preceding claims, wherein said slits (14) are made at a fitting (11) integral with said hollow body (3) , said fitting (11) beingpartially wrapped in the film (2) together with the respective hollow body (3) .

5. The method as claimed in any one of the preceding claims, and comprising advancing said hollow body (3) and the respective film (2) along a given feed path (P) through a cutting station (8) to make said flaps (15) and a removal station (10) to remove said film (2) .

6. The method as claimed in claim 5 and comprising rotating said hollow body (3) and the relative film (2) about the longitudinal axis by 90° in a rotation station (9) between the cutting station (8) and the removal station (10) along the feed path (P) .

7. The method as claimed in any one of the preceding claims and comprising performing the film tearing at a temperature above 90° C.

8. A system for removing a printing film from a hollow body (3) , around which the film (2) has been previously heat- shrunk and wherein the hollow body (3) extends along a longitudinal axis (A) , the method comprising:- at least one cutting device (13) configured to make two slits (13) in the film (2) at one end of the hollow body (3) so as to define two flaps (15) arranged on opposite sides of the hollow body (3) with respect to the longitudinal axis (A) ;- two gripping members (18) to grip the flaps (15) ; and- an actuator assembly (19, 20, 21, 25) configured to simultaneously advance the gripping members (18) and said flaps (15) integral with their respective gripping members (18) in two opposite directions with respect to the longitudinal axis (A) so as to tear the film (2) .

9. The system as claimed in claim 8, wherein the actuator assembly (19, 20, 21, 25) comprises two linear actuators (21) which support at their free ends the respective gripping members (18) and are configured to simultaneously advance the gripping members (18) and the respective flaps (15) along a direction parallel to the longitudinal axis (A) .

10. The system as claimed in claim 9, wherein the actuator assembly (19, 20, 21, 25) comprises a guideway (19) arranged above the conveyor transversely to the feed path (P) and two carriages (20) , which are selectively movable along the guideway by respective actuators (25) and are configured to support said linear actuators (21) .

11. The system as claimed in any one of claims 8 to 10, and comprising two cutting devices (13) for making said slits (14) in the film (2) at two opposite end sections of the film (2) so as to define said flaps (15) , in particular said slits (14) are parallel to the longitudinal axis (A) .

12. The system as claimed in claim 11, wherein the cutting devices (13) are configured to emit respective laserbeams at a fitting (11) integral with said hollow body (3) , said fitting (11) being partially wrapped in the film (2) together with the respective hollow body (3) .

13. The system as claimed in any one of claims 8 to 12, and comprising a conveyor (4) configured to advance said hollow body (3) and the respective film (2) along a given feed path (P) through a cutting station (8) for making the slits (14) and said relative flaps (15) and a removal station (10) for removing said film (2) .

14. The system as claimed in claim 13, wherein the conveyor (4) comprises a plurality of support devices (7) configured to support said hollow bodies (3) with their longitudinal axes (A) oriented in a vertical direction.

15. The system as claimed in claim 14, wherein the conveyor (4) comprises at least one rotation device (16) for rotating each support device (7) and the respective hollow body (3) around the longitudinal axis (A) by 90° in a rotation station (9) arranged between the cutting station (8) and the removal station (10) .

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