EP4620690A1

EP4620690A1 - Drying apparatus of a printed tape

Info

Publication number: EP4620690A1
Application number: EP25160835.2A
Authority: EP
Inventors: Natalino Arduini; Michele Bonizzato; Leone Francesco NARDON
Original assignee: Expert SRL
Current assignee: Expert SRL
Priority date: 2024-03-20
Filing date: 2025-02-28
Publication date: 2025-09-24

Abstract

A drying apparatus (1) of a printed tape (N) intended to be installed in printing machines (100); said apparatus (1) comprising a containment structure (2) configured to internally define an operative volume (3) between an inlet section (4) for said printed tape (N) and an outlet section (5) for said printed tape (N); handling means (6) operatively associated with said containment structure (2), said handling means (6) being configured to move said printed tape (N) from said inlet section (4) to said outlet section (5) and defining in said operative volume (3) a drying path (P) for said printed tape (N); drying means (7) arranged in said operative volume (3), configured to dry said printed tape (N) along said drying path (P); said handling means (6) define two or more portions (T1, T2) of said drying path (P) between said inlet section (4) and said outlet section (5); said two or more portions (T1, T2) of said drying path (P) being substantially overlapped with each other.

Description

Field of application of the invention

This invention relates to an apparatus for drying a printed tape, according to the preamble of the main independent claim no. 1.
The apparatus in question is advantageously used in the technical field of continuous printing of flexible tapes, and is intended to be installed in a printing machine, e.g. flexographic or coating or the like.
The invention also relates to a method for drying a printed tape, in particular by using said drying apparatus.
Thus, the apparatus (and/or method) that this invention relates to is advantageously used in the industrial sector of printing tapes of flexible material, in particular for drying the ink printed on said tape.
Furthermore, the apparatus (and/or method) that this invention relates to is advantageously used in the technical field of manufacturing and/or marketing printing machines (and/or devices or accessories thereof).

State of the art

Printing machines, whether flexographic, coating, or other, normally comprise an unwinding station, in which at least one reel of flexible material to be printed is rotatably mounted.
In addition, printing machines normally comprise a printing station operationally connected to the unwinding station and configured to receive a tape of flexible printing material from the unwinding station.
The printing station receives the tape of flexible material and impresses the desired print on one of its surfaces, resulting in a printed tape.
More specifically, printing involves the application of at least one ink on the surface of the flexible tape to be printed, for example for product packaging, for instance on tapes made of plastic, paper, aluminium, or the like.
Normally, the printed tape coming out of the printing station has the ink still wet and/or damp, so known printing machines comprise at least one drying apparatus for printed tape.
Finally, the printing machine normally comprises a winding station, configured to wind the dried printed tape into reels.
Conveniently, the ink used in flexographic printing comprises at least one base and at least one pigment.
The base used in said ink can be water-based or an organic solvent such as, for example, ethyl acetate or methoxypropanol.
Most known drying apparatuses are equipped with a containment structure defining an operative volume within it configured to contain appropriate handling means.
Said handling means are configured to move the printed tape within the containment structure, from an inlet section towards an opposing outlet section, to promote its drying.
More specifically, the containment structure is essentially box-shaped, in which the handling means define an essentially linear drying path within it between the inlet and outlet sections.
The known apparatus comprises, within the containment structure, drying means configured to dry the printed tape passing along the essentially rectilinear drying path, moved by the handling means.
For example, the drying means may comprise blowers that push hot air against the printed tape to be dried.
The apparatuses for drying a printed tape already on the market are also equipped with suction means configured to remove the volatile ink component (such as the above-mentioned organic solvent) that may be released from the printed tape during drying from the operative volume defined by the containment structure.
The main drawback of the drying apparatuses currently on the market lies in the fact that they have a large footprint, requiring a dedicated machine design that takes this space requirement into account.
In fact, the containment structure of the drying apparatuses must be large enough (between the inlet and outlet sections of the tape) to allow the printed tape to remain inside it long enough for the ink to dry.
Normally, to enable the drying apparatus to be used in drying all types of tapes and inks, the containment structure is several metres long.
Another drawback of known drying apparatuses lies in the fact that, although they have a great longitudinal extension, they do not completely dry the printed tape and some of the solvent is released in the form of a volatile compound once the tape leaves the containment structure.
Another drawback lies in the fact that the removal of the volatile compound produced during drying is never complete and often requires a lot of energy.
Another drawback lies in the fact that the volatile compound leaves the apparatus's containment structure, dispersing into the surrounding environment.
Normally, solvents used in printing ink are harmful to health if inhaled, creating a risk for operators in the area around the printing machine where the drying apparatus is installed.
Examples of prior art drying apparatuses are, for example, described in US 2021/291562 A1 , US 2020/086662 A1 , US 2018/264849 A1 , US 2020/164663 A1 , CN 108407436 A , US 2014/055541 A1 , US 2023/249475 A1 , WO 2021/044669 A1 , CN 110435298 A .
All of the above-identified prior art apparatuses, however, suffer from the above-mentioned drawbacks.

Description of the invention

This invention intends to overcome the above-mentioned technical drawbacks by providing a drying apparatus for a printed tape, preferably intended to be installed in printing machines, e.g. flexographic or the like, that can overcome and solve the drawbacks of the above-mentioned prior art.
The main purpose of this invention is to provide a drying apparatus for a printed tape that makes it possible to reduce the footprint of known drying apparatuses and, consequently, of the printing machines in which they are installed.
Another purpose of this invention is to provide a drying apparatus for a printed tape that allows the printed tape to be dried efficiently.
Another purpose of this invention is to provide a drying apparatus for a printed tape that minimises the undesirable release of the volatile solvent compound into the environment.
Another purpose of this invention is to provide a drying apparatus for a printed tape that minimises energy consumption and is cost-effective.
Another purpose of this invention is to provide a drying apparatus that can be easily installed, even as a replacement for known drying apparatuses already installed in printing machines.
Another purpose of this invention is to provide a drying apparatus that is structurally and functionally completely reliable.
Still, not the least purpose of this invention is to provide a drying apparatus for a printed tape whose use and operation is simple, rapid, and intuitive.
Another purpose of this invention is to provide a drying apparatus that has innovative and/or alternative features compared to known apparatuses.
These purposes, together with others that will be better elucidated below, are achieved with a drying apparatus for a printed tape of the type according to claim 1.
Other purposes that will be better described below are achieved with an apparatus in accordance with the dependent claims.
According to another aspect of this invention, a method is provided for drying of the type in accordance with claim 8, also intended to overcome the drawbacks of the above-mentioned known technique.

Brief description of the drawings

The advantages and features of this invention will become clear from the following detailed description of some preferred but non-limiting configurations of a drying apparatus for a printed tape with particular reference to the following drawings:

Figure 1 shows a schematic side view of a printing machine comprising a drying apparatus that is the subject of this invention;
Figure 2 shows a schematic side view of a detail of the machine illustrated in Figure 1, concerning a printing station and a drying apparatus according to this invention, with some parts removed to better highlight others;
Figure 3A shows another schematic side view of the apparatus that this invention relates to;
Figure 3B shows the view of Figure 3A with some parts removed to better highlight others.

Detailed description of the invention

This invention relates to a drying apparatus for a printed tape.
The apparatus that is the subject-matter of this invention is preferably intended to be installed in a machine for printing at least one tape, made of flexible material.
For example, the apparatus in question can advantageously be installed in a flexographic printing machine, or in a coating printing machine, or the like.
In general, the apparatus that is the subject-matter of this invention is advantageously used in any machine or plant where there is a need to dry and/or desiccate a tape of flexible material, in particular to dry the ink of a print.
In accordance with the particular but non-limiting embodiment illustrated in the attached figures, special reference will be made below to an apparatus advantageously installed or installable in a flexographic printing machine.
However, as mentioned above, the same apparatus must be understood to be installable in any type of printing machine, without thereby falling outside the scope of protection of this patent application.
The drying apparatus for a printed tape that this invention relates to has been identified as a whole by reference number 1 in the attached figures.
In addition, the (flexographic) printing machine in which the apparatus is preferably intended to be installed is indicated with the reference number 100 in the attached figures.
The drying apparatus 1 in question is therefore advantageously used in the technical field of printing, and in particular for printing on tapes of flexible material, particularly plastic, or paper or aluminium or the like.
More generally, the tape of material to be printed can be made of any material suitable to be handled by the flexographic printing machine; preferably, the tape is made of flexible material.
The printing machine 100 is per se known to the person skilled in the art and is therefore not described in detail below.
The machine 100 preferably comprise at least one support structure 101.
The support structure 101 of the machine 100 is advantageously intended to be placed on the ground.
The machine 100 (specifically for flexographic printing) comprises (in functional order) an unwinding station 102 of reels 107 of material tape to be printed M, a printing station 103 for tape M to obtain a printed tape N, a drying area 104 configured to dry the printed tape N, and a winding station 105, configured to wind the printed and dried tape onto reels 106.
Operatively, the tape passes through the machine 100 from the unwinding station 102 to the winding station 106, in particular through said printing station 103 and said drying area 104.
Obviously, the drying apparatus that is the subject matter of this invention is preferably intended to be mechanically mounted at said drying area 104 of the machine 100, i.e. operationally installed between the printing station 103 and the winding station 105.
More specifically, at said unwinding station 102 the at least one tape of flexible material to be printed M is unwound from at least one reel 107.
The machine 100 comprises suitable tensioning means 108 placed to intercept the tape to be printed M and the printed tape N in order to maintain the latter at a predetermined tension value.
The tensioning means can be of any type known to the person skilled in the art and will therefore not be described in detail below.
The printing station 103 is configured to imprint at least one print on at least one surface of the tape to be printed M to produce a printed tape N.
For example, the printing station 103 could be of the flexographic type, in accordance with the embodiment illustrated in the attached figures. In particular, the flexographic printing machine can be of the rotary or independent cylinder or stack type.
Obviously, the printing station 103 requires the use of at least one ink that is per se known to the person skilled in the art.
The ink comprises a pigment suited to imprint a predetermined colour and/or image onto the tape to be printed M and, preferably, a solvent suited to promote the resistance of said pigment once transferred onto the tape.
In accordance with one embodiment, the solvent of said ink can be water-based.
In a different embodiment, the solvent of said ink can be organic, for example ethyl acetate or methoxypropanol.
Normally, the ink used in said printing station 103 may comprise approximately 70%-90% solvent and 10%-30% pigments and/or other compounds.
As mentioned above, downstream from the printing station, the machine comprises the above-mentioned drying area 104, configured to dry ink (or similar compounds) present in wet or damp form on said printed tape N.
As mentioned above, the drying apparatus 1 of a printed tape N, which this invention relates to, is advantageously intended to be installed in printing machines 100, in particular for flexographic printing (in accordance with the embodiment illustrated in the appended figures), at the drying area 104.
The apparatus 1 in question comprises a containment structure 2 configured to internally define an operative volume 3 between an inlet section 4 for said printed tape N and an outlet section 5 for said printed tape N.
More specifically, the containment structure 2 is preferably substantially box-shaped and comprises multiple walls to delimit the operative volume.
The apparatus 1 according to the invention further comprises handling means 6 operatively connected to said containment structure 2.
The handling means 6 are configured to move the printed tape N from said inlet section 4 to said outlet section 5 and define a drying path P for said printed tape N in said operative volume 3.
The apparatus 1 also comprises drying means 7 arranged in said operative volume 3, configured to dry said printed tape N along said drying path P.
According to the invention, the handling means 6 define (and/or divide) two or more portions T1, T2 of said drying path P between said inlet section 4 and said outlet section 5.
The two or more portions T1, T2 of said drying path P substantially overlap each other.
In this way, the apparatus according to this invention makes it possible to reduce the footprint compared to the prior art apparatuses.
The apparatus 1 according to the invention can simultaneously reduce the footprint and increase energy efficiency, as will become clear below.
The containment structure 2 preferably extends along a prevailing extension direction X (identified in the attached Figure 3A).
Preferably, the containment structure 2 extends along the prevailing extension direction X between a first end 2' and a second end 2".
Preferably, the inlet section 4 is provided at the first end 2' of the containment structure 2 and the outlet section 5 is provided at the second end 2".
In accordance with a different embodiment, not illustrated in the attached figures, the inlet section 4 can be provided at the same end 2', 2" as the outlet section 5 or vice versa.
Advantageously, the containment structure 2 comprises multiple side walls, extending around and parallel to the prevailing extension direction X, to laterally delimit the operative volume 3.
The containment structure 2 also preferably comprises two end walls, provided at the first and second ends 2', 2" on which the inlet section 4 and the outlet section 5, respectively, are obtained.
Advantageously, the containment structure 2 is intended to be mechanically supported by the support structure 101 of the printing machine 100.
The containment structure 2 of the apparatus 1 is preferably intended to be mechanically supported at a higher elevation, preferably at a higher elevation than the unwinding station 102, the printing station 103 and the winding station 106, in accordance with the preferred but non-limiting embodiment of this invention illustrated in the attached figures.
Advantageously, a first portion T1 of said two or more portions T1, T2 extends along a first direction and a second portion T2 of said two or more portions T1, T2 extends along a second direction, different from said first direction.
Preferably, at least the first direction of the first portion T1 (and/or at least the second direction of the second portion T2) extends substantially parallel to the prevailing extension direction X.
In other words, at least the first direction of the first portion T1 (and/or at least the second direction of the second portion T2) preferably extends between the first end 2' and the second end 2" of the containment structure 2.
Obviously, the first direction of the first portion T1 (and/or the second direction of the second portion T2) may extend linearly or with any shape, for example arched, between the inlet section 4 and the outlet section 5, that is between the first end 2' and the second end 2" of the containment structure 2.
Preferably, the first portion T1 of the drying path P is substantially arched.
Preferably, the second portion T2 of the drying path is substantially arched.
The first, essentially arched portion T1 preferably defines a concavity facing the second overlapping portion T2.
In the same way, the second, substantially arched portion T2 preferably defines a concavity facing the first overlapping portion T1.
In other words, the first portion T1 and the second portion T2 are both arched and define a respective concavity facing in the opposite direction to each other.
In accordance with the preferred embodiment of this invention illustrated in the attached figures, the printed tape N, moving along said first portion T1 along said first direction, defines a first movement orientation V1 between said inlet 4 and said outlet 5 section.
In the same way, said printed tape N, moving along said second portion T2 along said second direction, preferably defines a second movement orientation V2 between said inlet section 4 and said outlet section 5, substantially opposite to said first movement orientation V1.
In other words, the printed tape N travels along the drying path P between the first end 2' (or from the inlet section 4) towards the second end 2" (or towards the outlet section 5) at the first portion T1 and, preferably, the printed tape N travels along the drying path P between the second end 2" (or from the outlet section 5) towards the first end 2' (or towards the inlet section 4) at the second portion T2, overlapping the first portion T1.
Advantageously, said drying means 7 comprise blowing elements 8 configured to emit, towards said handling means 6, at least one air knife, preferably having a temperature ranging between 50°C and 160°C.
The blowing elements of the drying means 7 preferably comprise one or more fans or compressors designed to generate a flow of drying air conveyed by means of suitable deflector means towards the printed tape N.
Advantageously, the handling means 6 are configured to engage a first face of the printed tape N.
Conveniently, the handling means 6 defining the drying path P are configured to engage only the first face of the printed tape N. In particular, the first face of the printed tape N engaged by the handling means 6 is not printed, i.e. it is not affected by the printing.
In this way, the handling of the printed tape M along the drying path avoids the risk that the still damp or wet ink should be ruined or compromised by the handling means 6.
With particular reference to the attached figures 3A and 3B, said handling means 6 preferably comprise a first set 11 of rollers, defining said first portion T1, and at least a second set 12 of rollers designed to define said second portion T2.
The rollers 11, 12 of the handling means 6 are preferably rotatably mounted on the support structure 2, within the operative volume 3.
The rollers 11, 12 of the handling means 6 are preferably operable in rotation about corresponding axes of rotation substantially orthogonal to the prevailing extension direction X of the containment structure 2.
Advantageously, the rollers 11, 12 of the handling means 6 may be active, i.e. directly driven in rotation by one or more motors (e.g. electric ones) or, alternatively, they may be passive, i.e. driven in rotation by the printed tape N.
Obviously, some of the rollers 11, 12 of the handling means 6 may be active and some passive, in any combination, without thereby falling outside the scope of protection of this patent application.
Advantageously, said handling means 6 comprise at least one deflecting assembly 10, suited to direct said printed tape N from the first portion T1 to a second portion T2 of said two or more portions T1, T2 of said drying path P.
Advantageously, in accordance with the preferred embodiment illustrated in the attached figures, said deflecting assembly 10 is interposed between said first set of rollers 11 and said second set of rollers 12 to change the movement direction of said printed tape N.
The deflecting assembly 10 preferably defines the end of the first portion T1 and the beginning of the second portion T2.
Preferably, the deflection assembly 10 is arranged in the vicinity of the second end 2" of the containment structure 2 and, preferably, in the vicinity of the outlet section 5.
Preferably, the deflecting assembly 10 comprises at least one roller rotatably attached to the containment structure 2 and driven in rotation around its axis of rotation, in particular essentially transverse to the prevailing extension direction X and parallel to the axis of rotation of the rollers 11, 12 of the handling means 6.
Preferably, the drying means 7 comprise a first set of blowers 8 arranged near the first set of rollers 11 of the handling means 6.
In addition, the drying means 7 preferably comprise a second set of blowers 8 arranged near the second set of rollers 12 of the handling means 6.
Preferably, the drying means 7 comprise at least one dryer 8 for each roller 11, 12 of the handling means 6.
Advantageously, each dryer 8 of the drying means 7 is arranged near a corresponding roller 11, 12 of the handling means 6.
More specifically, the drying means 7 are arranged on the opposite side of the printed tape M to the handling means 6.
In other words, the handling means 6 are intended to face the first (unprinted) face of the printed tape N, while the drying means 7 are intended to face a second (printed) face of the printed tape N to dry it.
The apparatus 1 preferably comprises heating means 13 configured to generate a flow of hot air intended to intercept the printed tape N to heat it.
The heating means 13 are preferably interposed between the handling means 6.
More specifically, the heating means 13 comprise at least one device for generating hot air, interposed between two adjacent rollers 11, 12 of the handling means 6 and configured to generate a flow of hot air, intended to intercept the printed tape N.
The heating means 13 are preferably configured to generate a flow of hot air, intended to intercept the first (unprinted) face of the printed tape N.
Preferably, the heating means 13 are arranged at the first set of rollers 11 of the handling means and, in particular, are preferably arranged in the vicinity of the inlet section 4 (and/or in the vicinity of the first end 2' of the containment structure 2).
Preferably, the device for generating a hot air flow of the heating means is configured to push the air flow through a plate that has multiple holes, before reaching the printed tape N. In this way, the hot air flow is homogeneous and at low speed, in order to heat the printed tape N without mechanically stressing it.
The Applicant actually carried out numerous tests to determine the maximum efficiency of solvent removal and ink drying. These tests found that heating the material that makes up the printed tape increases the evaporation of the solvent as a volatile compound within the operative volume 3.
Conveniently, the heating means 13 are configured to heat the printed tape N to a predetermined temperature.
In particular, with the printed tape N made of plastic material, the heating means 13 are preferably configured to heat the printed tape N to a temperature between 50°C and 110°C.
In addition, with the printed tape N made of paper, the heating means 13 are preferably configured to heat the printed tape N to a temperature between 60°C and 160°C.
Preferably, the temperature of all air inside the operative volume 3 is higher than the air temperature of the external environment.
In this way, the printed tape N remains heated as long as it remains inside the operative volume 3, running along the drying path P.
Advantageously, the apparatus 1 according to the invention comprises suction means 9 operatively connected to said containment structure 2.
Said suction means 9 are preferably configured to suck in at least one airstream from said operative volume 3, so as to draw from said operative volume 3 at least one volatile compound released from said printed tape N.
The suction means 9 preferably comprise at least one suction duct extending from suitable suction mouths 9' formed on the containment structure 2.
In addition, the suction means 9 comprise at least one fan or compressor (not shown in the attached figures) in fluidic communication with the suction mouths 9' and configured to suck in the airstream from the operative volume 3.
Advantageously, the airstream sucked in by the suction means comprises a portion of volatile solvent compound, in particular from the ink on the printed tape N.
Advantageously, the apparatus 1 according to the invention comprises burner means (not illustrated in the attached figures) operatively connected to said suction means 9.
Said burner means are preferably configured to burn at least one solvent of said volatile compound sucked in by said suction means, preferably in order to prevent the solvent from being dispersed into the environment.
More specifically, the burner means are configured to intercept an airstream sucked in by the suction means 9 from the operative volume 3 and to trigger combustion of the solvent present in the volatile compound of the airstream.
The solvent is actually typically ethyl acetate and/or methoxypropanol (PGME) and is flammable.
The compactness of the containment structure 2 and thus of the operative volume 3, made possible by the apparatus according to the invention, allows the suction means 9 to suck in an airstream containing a concentration of volatile compound (and thus of solvent) above a threshold value, in particular to allow complete and continuous burning of the same.
More specifically, the concentration of solvent in the volatile compound present in the airstream sucked in by the suction means is greater than or equal to a threshold value so that the combustion always remains active, avoiding the need for the burner means to light a pilot flame.
In other words, the burner means of the apparatus according to the invention do not consume fuel to maintain an active pilot flame, reducing energy consumption compared to the prior art apparatuses.
In addition, the apparatus 1 allows the removal of much more volatile compound with the same sucked in airstream, increasing the efficiency of solvent removal, up to an efficiency increase of about 30% compared to the known apparatuses.
Advantageously, said handling means 6 define a finishing path F, interposed between said drying path P and said outlet section 5.
As mentioned above, said printed tape N is preferably configured to release at least one volatile compound into said operative volume 3, at least along said finishing path F.
Advantageously, the finishing path F remains defined by the handling means 6 as a third portion T3, arranged downstream of the portions T1, T2 of the drying path.
Advantageously, the handling means 6 are configured to define a drying path P so that, at the end of the two or more portions T1, T2, the printed tape N is dry, i.e. the ink does not risk being ruined.
In this situation, the finishing path F is configured to keep the printed tape N heated and to force it to release the greatest possible quantity of solvent by means of the volatile compound, within the operative volume 3, to avoid its being dispersed in the environment when the printed tape N leaves the outlet section 5.
In fact, the finishing path F forces the printed tape N to remain within the operative volume 3, where the temperature is higher than in the external environment, consequently forcing the release of volatile compound and hence solvent.
The inclusion of the finishing path further increases the efficiency of solvent removal by evaporation as a volatile compound.
Advantageously, the handling means 6 comprise a second deflecting assembly 15, interposed between the drying path P and the finishing path F.
More specifically, the second deflecting assembly 15 is interposed between the second portion T2 of the drying assembly P and the third portion T3 of the finishing assembly F.
Advantageously, the second deflecting assembly 15 comprises at least one roller defining the end of the second portion T2 and the beginning of the third portion T3.
Preferably, the finishing path F is configured such that the printed tape N travels along the same finishing path F with a third orientation V3 essentially equal to the first orientation V1 of the first portion T1 and, preferably, essentially opposite the second orientation V2 of the second portion T2.
Advantageously, the second deflecting assembly 15 is arranged in the vicinity of the inlet section 4 (and/or in the vicinity of the first end 2' of the containment structure 2).
Conveniently, the finishing path F may comprise additional portions (not illustrated in the attached figures) without going beyond the scope of protection of this design.
This invention also relates to a method for drying a printed tape.
The method for drying a printed tape that is the subject matter of this invention is advantageously implemented using a drying apparatus for a printed tape of the type described above, the numerical references of which will be retained for simplicity of exposition.
All the features described with reference to the apparatus are to be understood, taken alone or in any combination thereof, also with reference to the method described below.
The method for drying a printed tape comprises at least the following operational steps:
Preliminarily, the method involves the introduction, in an operative volume 3 of a containment structure 2, of said printed tape N.
Subsequently, the method involves a step a) of moving said printed tape N in said operative volume 3 defined by a containment structure 2, from an inlet section 4 to an outlet section 5, through handling means 6 along a corresponding drying path P.
The method also involves a step b) of drying said printed tape N moving along said drying path P, through drying means 7 arranged in said operative volume 3 of said containment structure 2.
The method therefore preferably involves a step of exiting, through said outlet section 5, of said printed tape N from the operative volume 3 defined by the containment structure 2.
According to the invention, in said step b) the handling means 6 move said printed tape N along two or more portions T1, T2 of said drying path P between said inlet section 4 and said outlet section 5, said two or more portions T1, T2 of said drying path substantially overlap each other.
Said drying step b) preferably comprises a first sub-step of handling between the inlet section 4 and a first deflecting assembly 10 and at least a second sub-step of handling from said first deflecting assembly 10 to said outlet section 5.
Advantageously, the method according to the invention comprises at least the following steps.
The method preferably involves a step c) of suction of at least one airstream comprising at least one volatile compound released from said printed tape N during said step b) of drying through suction means 9 operatively associated with said containment structure 2.
The method preferably involves a step d) of burning said volatile compound of said airstream using burner means fluidically connected to said suction means 9.
Advantageously, said volatile compound sucked in at said step c) of suction has a concentration value in said sucked in airstream higher a minimum threshold value.
Advantageously, the method involves a step e) of running along a finishing path F, defined by the handling means 6 downstream of the drying path.
Said finishing path F preferably extends between said drying path P and said outlet section 5 for an additional length Δd.
Said additional length of said finishing path F preferably increases the dwell time of said printed tape N in said containment structure 2 by a corresponding time Δt.
In other words, compared to what happens in a drying station and/or step of a known printing machine, the printed tape N dried using the apparatus that this invention relates to must travel at least an additional distance Δd of the finishing path F that, for the same speed of travel, results in a longer dwell time within the operative volume 3.
During said additional dwell time Δt, said printed tape N additionally releases said volatile compound of said ink into the operative volume 3, thereby increasing the efficiency of the apparatus and method according to the invention.
The invention thus conceived therefore achieves all of the relative objectives.
This invention can be produced in other variants all falling within the scope of the inventive features claimed and described; these technical features can be replaced with different technically equivalent elements and the materials used; the invention can be of any shape or dimension as long as they are compatible with its use.
The numbers and reference marks included in the claims and description are only intended to increase the clarity of the text and must not be considered as limiting the technical interpretation of the objects or processes identified by them.

Claims

A drying apparatus (1) of a printed tape (N) intended to be installed in printing machines (100); said apparatus (1) comprising:
- a containment structure (2) configured to internally define an operative volume (3) between an inlet section (4) for said printed tape (N) and an outlet section (5) for said printed tape (N);

- handling means (6) operatively associated with said containment structure (2), said handling means (6) being configured to move said printed tape (N) from said inlet section (4) to said outlet section (5) and defining in said operative volume (3) a drying path (P) for said printed tape (N);

- drying means (7) arranged in said operative volume (3), configured to dry said printed tape (N) along said drying path (P);

characterized in that said handling means (6) define two or more portions (T1, T2) of said drying path (P) between said inlet section (4) and said outlet section (5);

said two or more portions (T1, T2) of said drying path (P) being substantially overlapped with each other.
Apparatus according to claim 1, characterized in that it comprises suction means (9) operatively associated with said containment structure (2), said suction means (9) being configured to suck in at least one airstream from said operative volume (3), so as to draw from said operative volume (3) at least one volatile compound released from said printed tape (N);
and that it comprises burner means operatively connected to said suction means (9), said burner means being configured to burn at least one solvent of said volatile compound sucked in by said suction means.
Apparatus according to claim 1 or 2, characterized in that a first portion (T1) of said two or more portions (T1, T2) extends along a first direction and a second portion (T2) of said two or more portions (T1, T2) extends along a second direction, different from said first direction;
said printed tape (N), moving along said first portion (T1) along said first direction, defines a first movement orientation (V1) between said inlet section (4) and said outlet section (5); said printed tape (N), moving along said second portion (T2) along said second direction, defines a second movement orientation (V2) between said inlet section (4) and said outlet section (5), substantially opposite to said first movement orientation (V1).
Apparatus according to one or more of the preceding claims, characterized in that said drying means (7) comprise blowing elements (8) configured to emit, towards said handling means, at least one air knife, preferably having a temperature between 50°C and 160°C.
Apparatus according to one or more of the preceding claims, characterized in that said handling means (6) comprise at least one deflecting assembly (10), suited to direct said printed tape (N) from a first portion (T1) to a second portion (T2) of said two or more portions (T1, T2) of said drying path (P).
Apparatus according to one or more of the preceding claims, characterized in that said handling means (6) comprise a first set (11) of rollers, defining said first portion (T1), and at least a second set (12) of rollers suited to define said second portion (T2); said deflecting assembly (10) being interposed between said first set of rollers (11) and said second set of rollers (12) to change the movement direction of said printed tape (N).
Apparatus according to one or more of the preceding claims, characterized in that said handling means (6) define a finishing path (F), interposed between said drying path (P) and said outlet section (5);
said printed tape (N) being configured to release into said operative volume (3), at least along said finishing path (F), at least one volatile compound.
Apparatus according to one or more of the preceding claims, characterized in that said burning means are configured to intercept an airstream sucked in by the suction means (9) from the operative volume (3) and to trigger a combustion of the solvent in the volatile compound of the airstream.
Apparatus according to one or more of the preceding claims, characterised in that said suction means 9 are configured to suck in an airstream containing a greater concentration of volatile compound than a threshold value.
Apparatus according to one or more of the preceding claims, characterised in that the concentration of solvent in the volatile compound in the airstream sucked in by the suction means is greater than or equal to a threshold value so that the combustion always remains active, to avoid the need for the burner means to light a pilot flame.
Apparatus according to one or more of the preceding claims, characterised in that said burner means are configured to keep a pilot flame alight without consuming fuel, thus reducing energy consumption compared to the prior art apparatuses.
Apparatus according to one or more of the preceding claims, characterized in that said handling means (6) define a finishing path (F), interposed between said drying path (P) and said outlet section (5).
said finishing path F remains defined by the handling means (6) as a third portions (T3), arranged downstream of the portions (T1, T2) of the drying path;

said handling means (6) being configured to define said drying path (P) so that, at the end of the two or more portions (T1, T2), the printed tape (N) is dry.
Apparatus according to one or more of the preceding claims, characterised in that said finishing path (F) is configured to keep said printed tape (N) heated and to force it to release the greatest possible quantity of solvent by means of the volatile compound, within the operative volume (3), so to prevent it from being dispersed in the environment following the exit of the printed tape (N) from the outlet section (5).
A method for drying a printed tape comprising at least the following operational steps:
a) moving said printed tape (N) in an operative volume (3) defined by a containment structure (2), from an inlet section (4) to an outlet section (5), through handling means (6) along a corresponding drying path (P);

b) drying of said printed tape (N) moving along said drying path (P), through drying means (7) arranged in said operative volume (3) of said containment structure (2);

in said step b) said handling means (6) move said printed tape (N) along two or more portions (T1, T2) of said drying path (P) between said inlet section (4) and said outlet section (5), said two or more portions (T1, T2) of said drying path are substantially overlapped with each other;

characterized in that it further comprises at least the following steps:
c) sucking in at least one airstream comprising at least one volatile compound released from said printed tape (N) during said step b) of drying through suction means (9) operatively associated with said containment structure (2);

d) burning said volatile compound of said airstream through burner means fluidically connected to said suction means (9).
Method for drying a printed tape according to claim 14, characterised in that said volatile compound sucked in said step c) of suction has a concentration value in said sucked in airstream higher than a minimum threshold value.