Process and machine for packaging boxed or rolled products.

Abstract

Process for packaging products (1; R1) with a packaging sheet (3) of paper material with a side (3 A) on which a heat-sensitive adhesive is distributed, comprising a double heating phase of an overlapping zone (Z3) of two flaps (3L, 3R) of the packaging sheet folded around the products (1; R1).

Description

[0001] TITLE

[0002] Process and machine for packaging boxed or rolled products.

[0003] DESCRIPTION

[0004] The present invention relates to a process and a machine for packaging boxed or rolled products.

[0005] In particular, although not exclusively, the present invention relates to the packaging of products such as tissue paper for drying hands or face, paper handkerchiefs and similar products contained in cardboard boxes from which the products can be removed individually. The present invention is equally applicable to the packaging of rolled products, such as rolls of tissue paper for hygienic use.

[0006] Generally, multiple boxes containing the above products are packaged for transport from the production site to storage depots and distribution or sales points in the form of packages in which multiple boxes are wrapped in a plastic film welded around the boxes that holds them together. Even the packages of paper rolls, such as tissue paper rolls for hygienic use and similar uses, generally involve wrapping the rolls with a plastic film. However, the market increasingly requires the use of recyclable materials such as paper. The use of paper as a packaging material has therefore become widespread and the packaging machines available today are generally configured to use paper instead of heat-sealable films. This paper has one side on which a heatsensitive adhesive is distributed, whose adhesive properties are activated by applying heat to the paper, and a non-adhesive side intended to form the external side of the package.

[0007] A problem that arises in the paper packaging of boxed products of the type mentioned above is that the packaging paper cannot be too thin because otherwise it breaks very easily, but if it is too thick it causes a slowdown in the packaging cycle because it requires excessive heat-sealing times and temperatures compared to current production needs. Similar difficulties are encountered in the packaging of rolled products such as tissue paper rolls for hygienic use and similar products.

[0008] US3248848, GB1036594 and US3429098 disclose systems for packaging products.

[0009] The main purpose of the present invention is to overcome the aforementioned drawbacks.

[0010] This result has been achieved, in accordance with the present invention, by implementing a process and providing a machine whose characteristics are indicated in the independent claims. Other characteristics of the present invention are the subject of the dependent claims.

[0011] Thanks to the present invention it is possible to package products such as tissue paper for drying hands or face, paper handkerchiefs and similar products contained in cardboard boxes, or even rolled products such as rolls of tissue paper for hygienic use, with pre-glued wrapping paper thick enough not to compromise the strength of the packages and at the same time without reducing the cycle times of the packaging process and ensuring adequate wrapping of the packaged products even if a packaging sheet is used that does not completely wrap the products but wraps them forming a simple containment band. Further advantages offered by the present invention are connected to the construction simplicity of the machine which can also be made as a retrofit of existing machines configured for the use of plastic film as packaging material. A packaging process in accordance with the present invention is also simple to implement with the use of automatic control systems currently available on the market.

[0012] These and further advantages and characteristics of the present invention will be better understood by any person skilled in the art thanks to the following description and the attached drawings, provided by way of example but not to be considered in a limiting sense, in which:

[0013] Fig.1 schematically represents a cardboard box containing paper handkerchiefs that can be removed from an opening formed on the upper side of the box itself; Fig.2 schematically represents a package made up of three cardboard boxes of the type shown in Fig.1;

[0014] Fig.3 schematically represents a package made up of four cardboard boxes of the type shown in Fig.1;

[0015] Fig.4 represents a schematic top plan view of a packaging machine according to the present invention;

[0016] Fig.5 represents a perspective view of a packaging machine in which the present invention can be implemented;

[0017] Fig.6 represents a detail relating to the entry of the products to be packaged into the machine shown in Fig.5;

[0018] Fig.7 represents a possible embodiment of a counter-folder with a heat-sealing bar on board; Fig.8 and Fig.9 represent possible embodiments of a device for forming lateral folds on the packaging sheet (Fig.8) and respectively a lateral heat-sealing device in a machine according to the present invention (Fig.9);

[0019] Fig.10 schematically represents the entry of a group of boxes into the packaging unit;

[0020] Fig.11 schematically represents a possible formation of the folds of the packaging sheet on the side ends of a package in a machine according to the present invention;

[0021] Fig.12 schematically represents the packaging of a group of toilet paper rolls in accordance with the present invention.

[0022] A packaging machine in accordance with the present invention can be configured, for example, to package a plurality of cardboard boxes (1) containing soft products such as tissue paper for drying hands or face, paper handkerchiefs (2) and similar products. The packages produced by the machine consist of a predetermined number of boxes (1) on which a wrapping sheet (3) made of paper material with an adhesive side (3 A) and an non-adhesive side (3B) is wrapped. A heat-sensitive adhesive is distributed on the adhesive side (3A) of the wrapping sheet (3) whose adhesive properties are activated by applying heat to the wrapping sheet. The wrapping sheet (3), as well as the boxes (1) intended to be packaged with the wrapping sheet (3) and the products contained in the boxes (1), are known. The packing sheet (3) is intended to wrap the set (G) of boxes (1) to be packaged on at least four sides, i.e. at least an upper side (1U), a lower side (IL), a front side (IF) and a back side (IB). In some cases, the packing sheet (3) may also wrap the set (G) of boxes (1) to be packaged at the lateral heads (10) of the same boxes.

[0023] Reduced to its essential structure and with reference to the figures of the attached drawings, a packaging machine in accordance with the present invention comprises: an entry station in which an inlet conveyor (Ml) is provided with a loading side (MIO) on which the boxes (1) to be packaged are loaded and an unloading side (Mi l); an elevator (M2) positioned in front of the unloading side (Mi l) of the inlet conveyor (Ml); a packaging unit (M3) comprising a respective entrance (M30) above the elevator (M2) for the entry of the boxes (1) into the packaging unit, a folder (M31) and a counter-folder (M32) configured to fold and overlap two flaps of the packaging sheet (3) underneath the boxes (1), the folder (M31) and the counter-folder (M32) being arranged and acting on the entrance (M30) of the packaging unit, a heat-sealing device (M33) configured to supply heat to the packaging sheet (3) after the folding and overlapping of said flaps, a sliding surface (M34) for the boxes (1) arranged downstream of the entrance (M30) with respect to a direction (FS) of advancement of the boxes (1) inside the packaging unit, a conveyor (M35) arranged above the surface (M34) box sliding surface configured to move the boxes along the aforementioned advancement direction (FS) on the sliding surface (M34), and an exit (M36) for the finished packages.

[0024] According to an operating scheme known to those skilled in the art, the boxes (1) to be packaged are loaded, arranged side by side, onto the input conveyor (Ml) which transports them to the elevator (M2). The latter is arranged in a lowered waiting position. Before introducing the boxes (1) to be packaged into the packaging unit (M3), a packaging sheet (3) is arranged above the elevator (M2), with the adhesive side facing downwards. Therefore, with the subsequent lifting of the elevator (M2), the boxes (1) to be packaged pass through the entrance (M30) of the packaging unit (M3) and intercept the packaging sheet (3). While the boxes (1) pass through the entrance (M30) of the packaging unit (M3), the packaging sheet (3) is subjected to an initial folding phase, wrapping the boxes (1) on the top and the sides as schematically shown in Fig.10. Subsequently, using the folder (M31) and the counter-folder (M32), the flaps (3L, 3R) of the packaging sheet (3) protruding vertically on the two sides of the package being produced are folded and overlapped underneath the boxes (1) so as to wrap the boxes (1) also on the bottom. In the drawings, the reference “3U” indicates the flap of the packaging sheet in contact with the top side of the boxes (1). The heatsealing device (M33), which for example can be positioned on board of the counterfolder (M32), supplies heat to the folded and overlapped flaps of the packaging sheet, simultaneously exerting a pressure on these flaps. In this way, the adhesive on the packaging sheet is activated in the zone affected by contact with the heat-sealing device (M3), so that the folded and overlapping edges of the packaging sheet are joined under the boxes (1). The conveyor (M35) controls the advancement of the packages on the surface (M34) along the advancement direction (FS) up to the exit (M36).

[0025] Depending on the size of the packaging sheet (3) and the type of packaging to be realized, the packaging unit (M3) may also feature, upstream of the exit (M36), a lateral folding device (M37), configured to obtain the folding of the packaging sheet (3) also on the two lateral heads of the boxes (1), and a lateral heat-sealing device (M38) acting on the packaging sheet (3) where the lateral folds are formed.

[0026] Examples of machines operating according to the operating scheme described above are provided in EP3980338B1 and EP4007724B1.

[0027] Advantageously, in accordance with the present invention, a heating unit (M39) is arranged in a predetermined position upstream of the exit (M36) of the packaging unit on the sliding surface (M34) for the packages being formed. The heating unit (M39) determines a new heating of the adhesive in the zone (Z3) of the folded and overlapped flaps of the packaging sheet underneath the boxes (1) previously subjected to the action of the heat-sealing device (M33) and, at the same time, the heating of the adhesive in an area (Z31) outside said zone. In other words, while the zone (Z3) of the folded and overlapped flaps of the packaging sheet underneath the boxes is subjected to heating again, the area (Z31) outside said zone is heated for the first time. In other words, the zone (Z3) of the folded and overlapping flaps of the packaging sheet underneath the boxes (1) is subjected to two heating actions (the first heating action exerted by the heat-sealing device M33 which also exerts a pressure, the second heating action exerted by the heating unit M39 downstream of the heat-sealing device M33 along the direction of advancement of the packages), while the area (Z31) outside said zone is heated only once (by the heating unit M39). Therefore, the joining of the flaps of the packaging sheet in the zone (Z3) where they are overlapped is consolidated due to the second heating action carried out by the heating unit (M39) downstream of the heatsealing device (M33). It is therefore possible to reduce the operating temperature of the heat-sealing device (M33) and / or the pressure exerted by the heat-sealing device (M33) on the flaps of the packaging sheet in the zone (Z3) where they overlap and / or reduce the duration of contact between said flaps and the heat-sealing device (M33). This allows the packages being formed to advance more quickly on the sliding surface (M34) and therefore to increase production without compromising the joint (J) in said zone (Z3). At the same time, the heating operated by the heating unit (M39) on the area (Z31) outside the joint (J) determines a thermo-activation of the adhesive in the same area (Z31) so that this area adheres to the lower part of the boxes (1). However, the adhesion of the area (Z31) of said flaps to the boxes (1) is such that the packaging sheet (3) can be easily detached when the user opens the package to use the products contained in the boxes, without damaging the latter. In practice, while in the zone (Z3) the adhesive that has previously received heat through the heat-sealing device (M33) is once again heated, such that in the zone (Z3) the joint (J) is formed by providing heat in two successive phases, in the area (Z31) there is only one heating phase (by means of the heating unit M39).

[0028] Consequently, the adhesion force of said flaps to the boxes (1) in the area (Z31) is lower than the adhesion force within the joint (J) in the overlapping zone (Z3) of the same flaps.

[0029] For example, said heating unit (M39) consists of an electrically heated fixed plate inserted into said surface (M35) so as to constitute an integral part of the surface itself. The heating unit (39) can be positioned, for example, immediately upstream of the exit (M36).

[0030] By way of example only, Figures 5-9 represent possible embodiments and / or operation of parts of a machine in accordance with the present invention, in particular the entrance (M30), the elevator (M2), the conveyor (M35), the folder (M31), the counterfolder (M32), the lateral folding device (M37) and the lateral heat-sealing device (M38).

[0031] With reference to Figs.5-9 of the attached drawings, at the entrance (M30) there is the elevator (M2) which moves inside a channel delimited by two lower vertical walls (2L) above which are arranged two upper vertical walls (2U), with a space (2S) between the lower vertical walls (2L) and the upper vertical walls (2U) in which the packaging sheet is inserted before the elevator is lifted. In Fig.6 the packages being formed, already inserted in the packaging unit (M3), are indicated by the reference “Cl”. The folder (M31) and the counter-folder (M32) are made up of horizontal surfaces, oriented parallel to the direction of advancement of the packages on the sliding surface (M34). On the counter-folder (M32) there is mounted an electro-heated bar which in this example constitutes the heat-sealing device (M33). This bar is mounted near a front edge of the counter-folder (M32) and is oriented transversely with respect to the direction of advancement of the packages on the sliding surface (M34). Said electroheated bar can assume a rest position below the counter-folder (M32) and a raised operational position protruding above the counter-folder itself, passing through a slot (SL) formed for this purpose on the counter-folder. EP3980338B1 discloses a mechanism for lowering and raising said electro-heated bar. It is understood, however, that the heat-sealing device (M33) does not necessarily have to be mobile as described in EP3980338B1 and does not necessarily have to be mounted on board the counter- folder. For example, the heat-sealing device (M33) could consist of an electrical resistance placed in a fixed position on the counter-folder, oriented for example as represented in the diagram in Fig.4. Again, for example, the heat-sealing device (M33) could consist of a heating surface arranged in a fixed position downstream of the entrance of the packaging unit. In the example shown in Fig. 5, the conveyor (M35) is formed by a plurality of groups of paddles (P35) mounted on bars (B35) which, in turn, are constrained to trolleys (C35) sliding along annular tracks provided on two sides of the conveyor. The paddles (P35) are oriented perpendicularly to the respective bars (B35) and these are oriented transversely to the direction of advancement of the packages inside the packaging unit. The annular tracks are of the linear motor type (for example, of the type commercially available under the trade name Beckhoff XTS series) so that each group of paddles (P35) can be moved, via the bars (B35) connected to the trolleys (C35), independently of the other groups of paddles, along an annular path that has always a lower section above the sliding surface (M34) of the packages. When a group of boxes (1) to be packaged is introduced into the packaging unit by the elevator (M2), in the infeed section of the packaging unit there are two groups of paddles (P35), one upstream and one downstream of the infeed section, forming a compartment in which the elevator inserts the boxes to be packaged and the packaging sheet before the folder and the counter-folder intervene. The movement of the paddles (P35) determines the advancement of the packages on the sliding surface (M34). The lateral folding device (M37) consists of two sets of brushes (S37) mounted on annular tracks (P37) arranged to the right and the left of the path followed by the packages being formed. Downstream of the annular tracks (P37) there are a fixed lateral counterfolder (F37), a helical folding guide (E37) and the lateral heat-sealing device (M38). In the example of Fig.9, the lateral heat-sealing device (M38) comprises two rows of electro-heated plates (P38) which have an internal side facing the path followed by the packages moving towards the exit (M36), and two belts (C38) closed in a ring so as to always have a section on the internal side of the respective rows of electro-heated plates (P38) and driven by respective electric motors (D38) so that said internal section follows the direction of the packages moving towards the exit (M36). The presence of the lateral folding device and the lateral heat-sealing device determines, using a packaging sheet of appropriate dimensions, the formation in sequence, on each lateral head of the boxes (1), of an upper fold (UF), two folds (US) facing the centre of the head, and a lower fold (UL) which overlaps the other folds (UF, US). As previously said, such a mechanical arrangement of the various parts which make up the packaging unit (M3) is known in itself (with the exception of the heating unit M39 arranged downstream of the heat-sealing device M33).

[0032] Fig.10 schematically shows a package comprising a group (G) made up of several rolls of tissue paper (Rl) arranged side by side on which the wrapping sheet (3) is wrapped. The packaging cycle for the rolls (Rl) is identical to that described above with reference to the boxes (1). In this case, however, given the convex shape of the rolls (Rl), the passage of the group (G) of products over the heating unit (M39) only determines the formation of the joint (J) in the zone (Z3) of overlapping of the lower flaps of the wrapping sheet (3) and not also the adhesion of the wrapping sheet to the paper of the rolls (Rl) outside the zone (Z3). Even in the case of packaging a group of rolls (Rl) the formation of folds in the wrapping sheet on the lateral heads of the products to be packaged can be foreseen in a similar way to that described above with reference to the boxes (1).

[0033] A process according to the present invention for packaging products (1; Rl) with a packaging sheet (3) of paper material with an internal side (3A) on which a heatsensitive adhesive is distributed and an external side (3B) which is not adhesive, therefore comprises the following operating steps performed sequentially: feeding, along a predetermined feeding direction (S), groups (G) of products (1 ; Rl) to be packaged with the wrapping sheet (3), said groups (G) being made up of a pre-established number of products (1; Rl) arranged side by side; feeding the packing sheet (3) for packaging each of said groups (G); moving each of said groups (G) of products (1; Rl) to be packaged along a direction (Y) orthogonal to said feeding direction (S) and intercepting a respective packaging sheet (3) such that the packaging sheet is placed above the products with the adhesive side (3 A) turned towards the products and there is the formation of a first flap (3U) of the packaging sheet in contact with an upper side of the products (1; Rl) and two lateral flap (3L, 3R) of the same packaging sheet, with the lateral flaps (3L, 3R) each protruding by a predetermined value beyond a lower side of the products (1; Rl); in a predetermined folding station, folding the lateral flaps (3L, 3R) underneath the products (1; Rl) overlapping one lateral flap (3L) on the other (3R) so as to form a zone (Z3) of overlapping of the lateral flaps (3L, 3R) in which the internal adhesive side (3 A) of a lateral flap (3L) is in contact with the external non-adhesive side (3B) of the other flap (3R), and an area (Z31) external to said overlapping zone (Z3), in which the internal adhesive side (3A) of the lateral flaps (3 L, 3 R) is in contact with the products (1; Rl) on a lower side of the products; in the same folding station where said area (Z3) and said zone (Z31) are formed or in a different station, providing heat and pressure on said zone (Z3) of overlap of the lateral flaps (3L, 3R) so as to thermally activate the thermosensitive adhesive distributed on the internal side (3 A) of the packaging sheet in correspondence with said overlapping zone (Z3), forming an adhesive joint (J); moving the products (1; Rl) and the packaging sheet of each group (G) along a predefined advancement direction (FS) until reaching a further operating station downstream of the folding station with respect to the advancement direction (FS); in said further operating station, provide heat again on said zone (Z3) of overlap of the lateral flaps (3L, 3R) so as to provide heat to said adhesive joint (J); moving the products (1; Rl) and the packaging sheet of each group (G) along said direction of advancement (FS) until reaching an exit station (M36) for the finished packages.

[0034] In accordance with the present invention, heat administration is carried out on an area (Z31) of the packaging sheet (3) external to said overlapping zone (Z3), the heating of said area (Z31) being operated simultaneously with the administration of heat to the adhesive joint (J) in said further operating station.

[0035] In the examples described above, when the products are contained in boxes (1) whose lower side is flat, heat is also supplied to said area (Z31) of the packaging sheet, while if the products are rolled up, heat that is supplied in the further operating station only in the zone (Z3) of overlapping of the lateral flaps (3L, 3R) underneath the products (Rl).

[0036] Optionally, a process in accordance with the present invention may also comprise a step of forming folds (UF, US, UL) of the packaging sheet (3) and of mutual heatjoining of such folds on the heads of the products (1; Rl). In this case, the step of further heat application on said zone (Z3) of overlapping of the lateral flaps (3L, 3R) underneath the products (1; Rl) may be performed either simultaneously with the phase of forming and heat-joining the folds (UF, US, UL) on the heads of the products (1; Rl) or before such phase or even subsequently. Preferably, the step of further heat administration on said zone (Z3) of overlapping of the lateral flaps (3L, 3R) underneath the boxes (1) is performed before the step of forming and heat-joining the folds (UF, US, UL).

[0037] From the foregoing description it is apparent that a machine in accordance with the present invention is a packaging machine comprising: an entry station in which an entry conveyor (Ml) is set up with a loading side (MIO) on which the products (1; Rl) to be packaged are loaded and an unloading side (Mi l); an elevator (M2) positioned in front of the unloading side (Ml 1) of the entry conveyor (Ml); a packaging unit (M3) comprising a respective entrance (M30) above the elevator (M2) for the entry of the products (1; Rl) into the packaging unit, a folder (M31) and a counter-folder (M32) configured to fold and overlap two flaps of the packaging sheet (3) underneath the products (1; Rl), the folder (M31) and the counter-folder (M32) being arranged and acting on the entrance (M30) of the packaging unit, a heat-sealing device (M33) configured to supply heat to the packaging sheet (3) after the folding and overlapping of said flaps, a sliding surface (M34) for the boxes (1) arranged downstream of the entrance (M30) with respect to a direction (FS) of advancement of the boxes (1) inside the packaging unit, a conveyor (M35) arranged above the sliding surface (M34) for the boxes configured to move the products (1 ; Rl) along the aforementioned direction of advancement (FS) on the sliding surface (M34), and an exit (M36) for the finished packages; wherein in a predetermined position upstream of the exit (M36) of the packaging unit, a heating unit (M39) is arranged on the sliding surface (M34) of the packages being formed, the heating unit (M39) being arranged downstream of the said heat-sealing device (M33) with respect to the said direction of advancement (FS).

[0038] The heating unit (M39) determines a new heating of the adhesive in the zone (Z3) of the folded and overlapping flaps of the packaging sheet underneath the products previously subjected to the action of the heat-sealing device (M33) and, at the same time, the heating of the adhesive in an area (Z31) outside this zone. From the preceding description it also appears evident that a machine in accordance with the present invention may also present one or more of the following characteristics, even combined with each other: said heating unit (M39) consists of an electrically heated fixed plane inserted in said sliding surface (M34) so as to constitute an integral part of the same surface. said heating unit (M39) is positioned immediately upstream of the exit (M36) for the finished packages.

[0039] - the elevator (M2) is inside a channel delimited by two lower vertical walls (2L) above which are placed two upper vertical walls (2U), with a space (2S) between the lower vertical walls (2L) and the upper vertical walls (2U).

[0040] - the packaging unit (M3) comprises means configured to perform, on the packaging sheet (3), further folds (UF, US, UL) on the heads of the products (1; R1).

[0041] The packaging sheet (3) may already be glued on the side (3 A) when it is inserted into the packaging machine, i.e. it may be a sheet already prepared with the adhesive side (3A), or it may be a sheet on whose side (3A) the heat-sensitive adhesive is distributed in a specific station of the machine using known methods. In practice, the execution details may however vary in an equivalent manner with regard to the individual elements described and illustrated, without thereby departing from the protection offered by this patent in accordance with the claims that follow.

Claims

CLAIMS1) Process for packaging products (1 ; Rl) with a wrapping sheet (3) of paper material with an internal side (3 A) on which a heat-sensitive adhesive is distributed and an external side (3B) which is not adhesive, comprising the following operational steps performed sequentially: feeding, along a predetermined feeding direction (S), groups (G) of products (1 ; Rl) to be packaged with the wrapping sheet (3), said groups (G) being made up of a pre-established number of products (1; Rl) arranged side by side; feeding the packing sheet (3) for packaging each of said groups (G); moving each of said groups (G) of products (1; Rl) to be packaged along a direction (Y) orthogonal to said feeding direction (S) and intercepting a respective packaging sheet (3) such that the packaging sheet is placed above the products with the adhesive side (3 A) turned towards the products and there is the formation of a first flap (3U) of the packaging sheet in contact with an upper side of the products (1; Rl) and two lateral flap (3L, 3R) of the same packaging sheet, with the lateral flaps (3L, 3R) each protruding by a predetermined value beyond a lower side of the products (1; Rl); in a predetermined folding station, folding the lateral flaps (3L, 3R) underneath the products (1; Rl) overlapping one lateral flap (3L) on the other (3R) so as to form a zone (Z3) of overlapping of the lateral flaps (3L, 3R) in which the internal adhesive side (3 A) of a lateral flap (3L) is in contact with the external non-adhesive side (3B) of the other flap (3R), and an area (Z31) external to said overlapping zone (Z3), in which the internal adhesive side (3A) of the lateral flaps (3 L, 3 R) is in contact with the products (1; Rl) on a lower side of the products; in the same folding station where said area (Z3) and said zone (Z31) are formed or in a different station, providing heat and pressure on said zone (Z3) of overlap of the lateral flaps (3L, 3R) so as to thermally activate the thermosensitive adhesive distributed on the internal side (3 A) of the packaging sheet in correspondence with said overlapping zone (Z3), forming an adhesive joint (J); moving the products (1; Rl) and the packaging sheet of each group (G) along a predefined advancement direction (FS) until reaching a further operatingstation downstream of the folding station with respect to the advancement direction (FS); in said further operating station, provide heat again on said zone (Z3) of overlap of the lateral flaps (3L, 3R) so as to provide heat to said adhesive joint (J); moving the products (1; Rl) and the packaging sheet of each group (G) along said direction of advancement (FS) until reaching an exit station (M36) for the finished packages; and in which heat is administrated to an area (Z31) of the packaging sheet (3) external to said overlapping zone (Z3), the heat administration to said area (Z31) being performed simultaneously with the heat application to the adhesive joint (J) in said further operating station.2) Process according to claim 1 wherein a step of forming folds (UF, US, UL) of the packaging sheet (3) and of mutual heat-joining of such folds on the heads of the products (1; Rl) is performed.3) Process according to claims 1 and 2 wherein the step of further heat administration on said overlapping zone (Z3) of the lateral flaps (3L, 3R) underneath the products (1; Rl) is performed simultaneously with the step of forming and heat-joining the folds (UF, US, UL) on the heads of the products (1; Rl).4) Process according to claims 1 and 2 wherein the step of further heat administration on said overlapping zone (Z3) of the lateral flaps (3L, 3R) underneath the products (1; Rl) is performed before the step of forming and heat-joining the folds (UF, US, UL) on the heads of the products (1; Rl).5) Process according to claims 1 and 2 wherein the step of further heat administration on said overlapping zone (Z3) of the lateral flaps (3L, 3R) underneath the products (1; Rl) is performed after the step of forming and heat-joining the folds (UF, US, UL) on the heads of the products (1; Rl).6) Packaging machine comprising: an entry station in which an entry conveyor (Ml) is set up with a loading side (MIO) on which the products (1; Rl) to be packaged are loaded and an unloading side (Mi l); an elevator (M2) positioned in front of the unloading side (Ml 1) of the entry conveyor (Ml); a packaging unit (M3) comprising a respective entrance (M30) above the elevator (M2) for the entry of the products (1; Rl) into the packaging unit, afolder (M31) and a counter-folder (M32) configured to fold and overlap two flaps of the packaging sheet (3) underneath the products (1; Rl), the folder (M31) and the counter-folder (M32) being arranged and acting on the entrance (M30) of the packaging unit, a heat-sealing device (M33) configured to supply heat to the packaging sheet (3) after the folding and overlapping of said flaps, a sliding surface (M34) for the boxes (1) arranged downstream of the entrance (M30) with respect to a direction (FS) of advancement of the boxes (1) inside the packaging unit, a conveyor (M35) arranged above the sliding surface (M34) for the boxes configured to move the products (1 ; Rl) along the aforementioned direction of advancement (FS) on the sliding surface (M34), and an exit (M36) for the finished packages; wherein in a predetermined position upstream of the exit (M36) of the packaging unit, a heating unit (M39) is arranged on the sliding surface (M34) of the packages being formed, the heating unit (M39) being arranged downstream of the said heat-sealing device (M33) with respect to the said direction of advancement (FS), and in which- the heating unit (M39) determines a new heating of the adhesive in the zone (Z3) of the folded and overlapping flaps of the packaging sheet underneath the products previously subjected to the action of the heat-sealing device (M33) and, at the same time, the heating of the adhesive in an area (Z31) outside said zone.7) Packaging machine according to claim 6 wherein said heating unit (M39) consists of an electrically heated fixed plate inserted in said sliding surface (M34) so as to constitute an integral part of the same sliding surface.8) Packaging machine according to claim 6 wherein said heating unit (M39) is positioned immediately upstream of the exit (M36) for the finished packages.9) Packaging machine according to claim 6 wherein the elevator (M2) is inside a channel delimited by two lower vertical walls (2L) above which two upper vertical walls (2U) are arranged, with a space (2S) between the lower vertical walls (2L) and the upper vertical walls (2U).10) Packaging machine according to claim 6 wherein the packaging unit (M3) comprises means configured to realize, on the packaging sheet (3), further folds (UF, US, UL) on the heads of the products (1; Rl).

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