ES2345936T3 - LAMINAR PACKAGING MATERIAL WITH REGISTRATION MARK. - Google Patents

Abstract

A sheet packaging material including a crease line pattern (4) comprising first crease lines (4a) in a longitudinal direction and second crease lines (4b) in a transverse direction and at least a register mark (19) defined by a surface topographic modification that is obtainable in the same production step as the crease line pattern (4) so as to be in register with said crease pattern (4); the register mark (19) includes two pairs of lines (21, 22; 23, 24) that are inclined with respect to the transverse direction by an angle ranging from 15 to 35 , the lines of one pair (21, 23) being parallel to one another and inclined with respect to the transverse direction by angle ± in a first direction, the lines of the other pair (22, 24) being parallel to one another and inclined with respect to the transverse direction by the same angle ± in the opposite direction.

Description

Laminated packaging material with brand registry.

The present invention relates to a material of laminar packaging, according to the preamble of claim 1, in Particularly a packaging material in the form of a strip for packaging pourable food products, which has a registration mark to detect the position of the material in a machine packing machine

As is known, packages containing products pourable food such as milk, fruit juice, salsa Tomato or wine are manufactured in packaging machines from one band of packaging material or from pieces of material laminate.

In the case of a continuous web material, the band, which is fed out of a coil and sterilized through of an aseptic chamber, bends longitudinally and sealed to form a continuous vertical tube that is filled with the product food and seals transversely to form so-called Pillow-shaped packages using pairs of jaws sealed that are placed cyclically in contact with the tube.

Pillow-shaped containers are separated subsequently from each other cutting along the lines of sealed transverse and fold in its final form substantially parallelepiped.

During the training, the band material will be submits a few bending steps along some folding lines predetermined that are stamped on the web material; with in order to ensure that the training steps are carried out in registration with the pattern of folding lines, the position Longitudinal band is detected by perceiving the position of optically detectable evidence, for example printed marks, which are repeated throughout the web packaging material according to a step (repetition length) that is equal to the length of Repeating the folding pattern. In response to the position of the registration mark is detected sooner or later than a reference time, a device called "correction of design "acts on the containers that are being formed to remove more or less material in the feed direction.

For many years some brands have been used printed to detect the longitudinal position of the material in band, brands are simple to produce and easy to read; from In fact, the printed brand is simply a portion of the design of the packaging and therefore does not incur any additional cost. Without However, being a portion of the printed design means that the brand of registration itself is not perfectly in register with the employer folding, because the printing and folding steps are two successive different steps in the production of band material and, although the relative displacements between the two steps are they keep to a minimum, there are inherent tolerances in the process of production.

The document EP-A-0 772 760 describes a method and a device to detect the position of a folding line of a material in packaging band by means of a technology of laser reflection, in particular using two photodetectors that detect the light reflected by the material over two inclined directions with respect to the direction of incidence of the light and processing the signals thus obtained.

If a fold line is used as a "mark registration ", the position of the web material in one direction given, for example longitudinal, can be detected with this method, assuming the line is correctly identified with with respect to the other folding lines that form the pattern of folding lines This would require using a reference code additional, for example a printed code, to fire a "reading window".

Likewise, the position of the web material in a transverse direction perpendicular to the feeding direction; this is the case both when the band material is still flat, but experiences preliminary operations on the machine, such as cutting, application of removable pins or opening devices, such as when the tube is already formed, to control the "tube torsion", is that is, the torsion movement of the tube around its axis longitudinal.

In these cases different indications are used optically readable, such as the position of a shore of the band, or pre-laminated holes for opening devices, or the longitudinal seal of the tube; However, these indications They are difficult to detect and in any case require sensors dedicated.

Attempts have been made in the past to solve the aforementioned problems. WO documents 03/037729 and WO 03/037722 describe the use of folding lines for detect both the longitudinal and transverse position of the band material. However, the solution provided is not totally satisfactory because it has been proven to be difficult to "select" the correct folding lines that they have to detect among the various lines that constitute the folding pattern without firing a "reading window" by medium of a conventional brand printed type. Although it turns out effective to eliminate the "printing to folding ", this solution still requires two detection systems, one for printed signs and the other for fold lines.

Documents DE-A-10246449 and EP-A-1 406 061 describe a method to detect the longitudinal and transverse position of a material in band packaging by reading two stamped lines mutually intersecting through reflection technology laser differential similar to that described in the document EP-A-1 406 061 mentioned above. Without However, this method cannot provide all the data that is necessary to control the power of the band because information on the speed of the band cannot be obtained, which It is an essential parameter that has to be detected and must be determined in some other way.

WO 2004/018190 describes a material of laminar packaging as defined in the preamble of the claim 1.

An object of the present invention is to design a laminar packaging material provided with a registration mark that overcome the drawbacks of the prior art, that is, be in register with the folding pattern, which can be read selectively with respect to the folding pattern and that does not require "external" auxiliary clues to fully establish the longitudinal and transverse position of the sheet material, as well as its speed

A further object of the present invention is design a laminar packaging material provided with a brand of record that can be manufactured without a substantial increase in production costs compared to known materials Currently in use.

This object is reached with a material of laminar packaging as claimed in claim 1.

Embodiments will be described below. Preferences of the present invention by way of examples not limiting and with reference to the attached drawings, in the that:

Figure 1 illustrates a portion of a material in web packaging according to an embodiment of the present invention;

Figure 2 schematically shows a machine Forming / filling machine to produce aseptic containers from band material of figure 1;

Figure 3 shows a detail of the material of Figure 1, on an enlarged scale, including a mark of registry;

Figure 4 is a partial cross section enlarged band material taken along the line IV-IV of Figure 3;

Figure 5 is a perspective view schematic of a detection device to detect the mark of registration of figure 3;

Figures 6, 7 and 8 show schematically three different exploration situations in which the brand of register is respectively centered, shifted to the side and shifted to the other side with respect to the device detection;

Figure 9 is a diagram showing signals generated by the detection device in corresponding cases to figures 6, 7 and 8;

Figures 10, 11 and 12 illustrate embodiments registration mark alternatives;

Figure 13 is a cross section of the band material taken along the line XIII-XIII in Figure 12; Y

Figures 14 and 15 illustrate embodiments alternatives of a part of the registration mark.

The number 1 in Figure 1 indicates a portion of a laminar packaging material 2 fed in the form of a band continue 3.

Band 3 of material 2 comprises a pattern 4 fold lines and a printed design 5, which are repeated about R intervals equal to the length of the material required for produce a container Pattern 4 of folding lines includes, of in a known way, a plurality of fold lines longitudinal 4a, corresponding to the vertical corners of the finished containers, and a plurality of folding lines transversal 4b corresponding to the horizontal corners of the container and base of the portions or "fins" of sealing transversal.

4c inclined fold lines, mainly inclined at 45º but also present with angles different with respect to the longitudinal direction, they appear in the upper and lower parts of the pattern and define the lines of folded from the flaps of the container.

Band 3 can be used on a machine 6, shown schematically in figure 2, to produce containers aseptic and on which the band 3 is unwound from a coil 7 and is fed through an aseptic chamber (not shown), in where it is sterilized, and through a set 8 by which it is folded and sealed longitudinally to form, in a way known, a continuous vertical tube 9.

The tube 9 of packaging material is filled continuously with the pourable food product by means of a known filling device 10, and subsequently fed to a forming and transverse sealing post 14 where grabs it between a pair of jaws (not shown) that seal transversely the tube to form packages 15 in the form of pillows

Packages 15 in the form of pillows are separated subsequently cutting the sealing portion between the packages and they are fed to a final folding post 16 where they are folded mechanically to form the finished containers 17.

The containers are formed by folding the material at along the folding lines 4a, 4b, 4c and controlling the material feeding by means of an optical detector device 18 to "read" registration marks 19 located on the material a R. intervals

According to the present invention, each registration mark 19 includes at least four inclined lines 21, 22, 23 24 defined by topographic surface modifications of the web material obtained during the folding process and detectable by means of the detecting device 18, which is conveniently based in differential laser reflection technology according to the principle of EP-A-0 772 760, as best described below.
tion.

Two of the lines (21, 23) are parallel to each other and are inclined with respect to the transverse direction under an angle? In a first direction, and the other two lines (22, 24) are parallel to each other and are inclined with respect to the longitudinal direction under the same angle α in the opposite direction. The angle? Conveniently ranges between 15 ° and 35 °. These angle values are sufficiently far from the inclination of the standard folding lines 4a, 4b, 4c to provide a good recognition of the lines 21, 22, 23, 24 by the detector device
18.

In the embodiment of Figure 3, the four lines 21, 22, 23, 24 are defined by fold lines by compression, that is, lines obtained using a folding cylinder with radially protruding ribs and a counter cylinder purely cylindrical, that is, without any indentation correspondent. The result of this is a local compression only on one side of the web material 3 (see detail in enlarged cross section of figure 4) having a shape substantially trapezoidal.

This technology has proven to be advantageous versus standard folding technologies that use tools male-female folding because the edges side of the folding lines are sharp, as opposed to bulging edges that are generally obtained by processes folding standards.

In addition, according to the embodiment of Figure 3, the lines 21, 23 and 22, 24 intersect at their midpoints, with the in order to define two "crosses" 27, 28 that are separated from one of another in the longitudinal direction. At the intersection points, in order to minimize light scattering, the lines can be interrupted locally, leaving a zone substantially not compressed 29 as shown in figures 14 or 15.

Figure 5 is a schematic view showing a possible embodiment of the detector device 18. A transmitter 30 Central laser beam includes a single laser source and a diffraction lens unit, both not shown in given detail which are known per se, to generate two flat laser beams 31, 32 which are directed perpendicularly to the band material 3 and intersecting along an axis B. The two beams 31, 32 of lasers can be considered as a single laser beam 35 that has X shape in cross section; of course, the two branches of the "X" have the same inclination as 21, 23 and 22, 24, respectively.

The detector device 18 further includes two pairs of laser detectors 33, 34, 35, 36 arranged around of the emitter 30. The laser detectors 33, 35 are located at opposite sides of the emitter 30, in a plane containing the B axis and is arranged at an angle to the plane of beam 31de laser, that is, with respect to lines 21, 23, in order to detect differential reflection produced when beam 31 passes on lines 21, 23. The laser detectors 34, 36 are located on opposite sides of the emitter 30, in a plane containing to the B axis and is arranged at an angle to the plane of the beam 32 laser, that is, with respect to lines 22, 24, in order of detecting the differential reflection produced when beam 32 passes on lines 22, 24.

The detector device 18 is connected to a control unit 40 that controls the power of the band in response to signals received from detectors 33, 34, 35, 36 of To be.

Figures 6 to 8 show the principle of operation of the longitudinal and transverse detection of web material according to the present invention.

In the case of figure 6, the position transverse of the web material 3 is centered, that is, the centers of crosses 27, 28 of registration mark 19 are aligned with axis B. In this case, being T1, T2, T3 and T4 the times in which lines 21, 22, 23 and 24, T1 are detected It is equivalent to T2 and T3 is equivalent to T4. Therefore the displacement lateral is zero.

In the case of figures 7, T1 will precede T2 and T3 will precede T4; in the case of figure 8, T2 will precede T1 and T4 will precede T3.

The three situations are reflected in the figures 9 a), b) and c) where reflection signals are recorded depending on weather. In each situation, the difference \ DeltaT_ {1,2} between T1 and T2 (if it exists) equals the difference \ DeltaT_ {3,4} between T3 and T4.

With reference to the scheme in Figure 8, and being:

D =

distance between crossing centers,

W =

one half the width of a cross in the direction cross,

E =

lateral displacement of the web material with with respect to its transverse reference position of Figure 6; Y

A =

the distance covered by the web material during the time ΔT1 {1,2},

the following relationships apply geometric:

[one]

E / A = W / D and

[2]

W = D / 2tg?,

where:

[3]

E = A / 2tgα.

In addition, D being the distance covered during the time ΔT_ {1; 3} = T3-T1,

[4]

A = D * \ DeltaT_ {1,2} / ΔT 1,3.

If the value of α is, for example, 26.5 °, then tg? = 0.5, in which case the expressions [3] and [4] They are further simplified to express:

[5]

E = A = D * \ DeltaT_ {1,2} / ΔT 1,3.

The above explains how they can be calculated transversal deviations by the control unit 40 and how they can  the corresponding control signals are generated.

The speed of the band can also easily calculated, for control purposes, based on the following expression:

[6]

v = D / \ DeltaT_ {1,3}.

Finally, as is well known in the technique, the control unit 40 generates an impulse signal T of register (figure 2) to control the longitudinal feeding of the band (design correction). The 19th registration mark of the The present invention makes it possible to make such a signal independent of the lateral displacement and band speed, as well as avoid any fluctuation (deviations in the timing of signal).

Referring again to the diagrams of Figures 9 b) and c), the following approach can be used.

A recording pulse T is generated in a moment corresponding to the "reading" of the second cross 28 when not There is lateral displacement. This is done by reading the first three impulses that come from the laser detectors at the moment T1, T2, T3 (or T2, T1, T4, as the case may be), calculating ΔT_ {1,2} and applying a delay of ½ ΔT_ {1,2} to the readings of T3 or T4, whichever comes first. This delayed pulse is pulse T. Therefore, pulse T will be free of fluctuations and can be easily compared to a clock pulse, in a known way, to determine if the Band material is "fast" or "slow" and thus control The design correction mechanism.

Figures 10, 11 and 12 describe different embodiments of the registration mark 19, which, however, are all of them based on the use of topographic modifications of the surface of the web material forming two pairs of lines parallel.

The example in figure 10 is similar to the one already described, with the only difference that lines 21, 24 have one end in common to form a V and that, similarly, the lines 22, 23 have a common opposite end in order to form an inverted V. Lines 21, 22 and 23, 24 intersect in about respective intersection points P1 and P2. According to this configuration, within the range of lateral displacement between P1 and P2 lines 21, 22, 24 and 23 are always detected in this order, which simplifies recognition individual lines in case a dispersion occurs substantial of the light by the band material, with which the lines 21, 23 are also detected by detectors 34, 36 and, vice versa, lines 22, 24 are also detected by the detectors 33, 35. If this is the case, only two detectors can be used,  in front of four.

The arrangement of Figure 11, in which the two inverted Vs are not partially overlapping but are quite different from each other, guarantees that lines 21, 24, 23, 22 are always read in this order; although the dimensions Registration mark totals are larger, this provision allows a wider range of transverse displacements correctable.

Since the order of the lines is fixed, only two detectors can also be used in this case if the dispersion of the light is high enough.

Finally, the arrangement of Figure 12 is very similar to that of figure 3 in terms of linear geometry; from again, lines 21, 22, 23 and 24 form two shifted crosses a with respect to another in the direction of band feed. Without However, in this case lines 21 to 24 are not defined by compression folding lines, but rather by some lines of transition between surfaces 43, 44 of different level. In particular, such lines are defined by the sides of a plurality of patterned portions 43 alternating with portions unmodified surface 44 of the web material. Such lines they are, in cross section, "steps" between portions stamped 43 and unmodified portions 44 (figure 13).

In order to produce lines 21, 22, 23, 24, stamped portions 42 are defined by three triangles isosceles 50, 51, 52 and two right triangles 54, 55 which are equal to one half of an isosceles triangle. Two of the isosceles triangles 50, 51 have their bases aligned in the feed direction of the band and a common base vertex, the third isosceles triangle 52 has its base vertices coinciding with the upper vertices of the first two triangles The right triangles 54, 55 are located waters up and downstream of the third isosceles triangle in the direction longitudinal of the band, each with its short leg aligned in the longitudinal direction of the band and with its hypotenuse aligned with one side of a respective isosceles triangle 51, 50.

The asymmetric reflection pattern that originates when the laser beam scans a "step" it allows to detect which specific line 21, 22, 23, 24 is being detected, given that lines 21, 23 which has a first step profile, by example of "high to low", will originate a first pattern of reflection and lines 22, 24 that have a second profile of step, for example from "low to high", will originate a second reflection pattern. As a consequence, if the light scattering is high enough, even with only two detectors, which allows the use of a simpler detector device 18 and cheap.

Based on the description above, they are clear the advantages of the present invention over the technique previous. Registration marks 19 are in perfect registration with the folding pattern, can be read selectively with respect to the folding pattern and do not require "external" reference or auxiliary clues, such as printed optical codes, for fully establish the longitudinal and transverse position of the Band material and its speed.

Claims (8)

1. A laminar packaging material that includes a pattern (4) of folding lines comprising first folding lines (4a) in a longitudinal direction, second folding lines (4b) in a transverse direction, some third lines of folded (4c), inclined mainly at 45º with respect to the longitudinal direction, and at least one registration mark (19) defined by a surface topographic modification obtainable in the same production step as the pattern (4) of folding lines with in order to be registered with said folding pattern (4), including the registration mark (19) a plurality of lines (21, 22, 23, 24), characterized in that the registration mark includes at least two pairs of lines (21, 22; 23, 24) that are inclined with respect to said transverse direction under an angle ranging from 15 ° to 35 ° and is sufficiently far from the inclination of said first, second and third fold lines (4a, 4b, 4c) to provide a good recognition by a detector device (18), the lines of one pair (21, 23) being parallel to each other and being inclined with respect to the transverse direction under said angle α in a first direction , the lines of the other pair (22, 24) being parallel with each other and being inclined with respect to the transverse direction under the same angle α in the opposite direction. 2. A material according to claim 1, characterized in that said lines (21, 22, 23, 24) form two crosses (27, 28) that are separated from each other in said longitudinal direction. 3. A material according to claim 1, characterized in that said lines (21, 22, 23, 24) form two opposite Vs. 4. A material according to claim 3, characterized in that said Vs intersect with each other. 5. A material according to any of the preceding claims, characterized in that said lines (21, 22, 23, 24) are lines obtained by compression. A material according to any of the preceding claims, characterized in that said lines are defined by steps between stamped areas (43) and areas (44) without deformation and of said material. 7. A material according to any of the preceding claims, characterized in that it has the form of a continuous band (3) having said pattern (4) of folding lines and said registration mark (19) repeated thereon at a repetition length fixed (R) along the longitudinal direction. A material according to claim 5, characterized in that said lines (21, 22, 23, 24) obtained by compression are interrupted by an uncompressed area (29) at an intersection point.