EP2669230A1

EP2669230A1 - Unrolling group for fabric printer apparatus

Info

Publication number: EP2669230A1
Application number: EP12170135.3A
Authority: EP
Inventors: Paolino Gastoldi
Original assignee: La Meccanica Costruzione Macchine Tessili SpA
Current assignee: La Meccanica Costruzione Macchine Tessili SpA
Priority date: 2012-05-31
Filing date: 2012-05-31
Publication date: 2013-12-04

Abstract

It is provided an unrolling group (1) for a fabric (10a) printer apparatus (100) comprising a supporting structure (20) adapted to enable the unrolling group (1) to be disposed on a rest surface (1b); an unrolling unit (30) adapted to support a reel (10) of fabric (10a) and defining an unrolling axis (30a); an extending apparatus (40) adapted to tightly stretch the fabric (10a) supplied from said reel (10) comprising a take-up member (41) defining a sliding surface (41) for the fabric (10a) and comprising a constraint (46) adapted to connect the take-up member (41) in a motion-admitting manner to the supporting structure (20) so as to enable the take-up member (41) itself to rotate relative to an oscillation axis (41 a) transverse to the unrolling axis (30a).

Description

The present invention relates to an unrolling group for fabric printer apparatus of the type pointed out in the preamble of the first claim.
In particular, the invention relates to an unrolling group belonging to a printer apparatus of natural fabrics, cotton or linen for example, and/or fabrics of synthetic origin such as polyester and Lycra^®. More particularly, the invention relates to an unrolling group of a fabric printer apparatus of the inkjet type.
It is known that unrolling groups, belonging to printer apparatus, are adapted to unroll the fabric and lay it on a conveyor belt or other conveying member adapted to take the fabric itself to a printing unit carrying out printing of the fabric.
To this aim, known unrolling groups comprise an unrolling cylinder adapted to support a rolled-up fabric, or reel, and one or more tension rollers that, being suitably offset, enable the fabric to be stretched out so that it is disposed on the belt perfectly taut and smooth in order to offer a flat surface for printing.
The known art mentioned above has some important drawbacks.
A first important problem is represented by the fact that, in spite of the presence of tension rollers, the fabric, when it reaches the belt, does not appear to be perfectly taut, thereby defining a printing surface that is not perfectly flat and is therefore capable of giving rise to print errors.
This problem is particularly apparent when the fabric, due to working errors and/or defects, has an uneven shape that therefore is not adapted to ensure perfect arrangement of the fabric at the printing unit. In particular, in fabric rolls or reels still to be printed, due to said working errors, creases, pleats and/or gathering effects can often be found that do not allow optimal laying out of the fabric to be obtained.
Another problem is therefore represented by the fact that, due to said print errors, the production is characterised by high amounts of rejects and therefore is very expensive and of little efficiency.
A further problem resides in that, due to the difficulties in spreading the fabric out, known unrolling groups and consequently printers presently in use do not operate at high rates for the purpose of reducing this problem and in an attempt of minimising the production rejects.
Under this situation, the technical task underlying the present invention is to conceive an unrolling group for fabric printer apparatus capable of substantially obviating the mentioned drawbacks.
Within the scope of this technical task it is an important aim of the invention to obtain an unrolling group for printer apparatus that is able to ensure almost perfect tensioning of the fabric.
Another important aim of the invention is to obtain an unrolling group ensuring high production rates and practically the absence of rejects.
It is therefore a further aim of the invention to provide an unrolling group for fabrics enabling a particularly cheap production to be obtained which is also efficient in terms of printing.
The technical task and the aims specified are achieved by an unrolling group for fabric printer apparatus as claimed in the appended claim 1.
Preferred embodiments are highlighted in the sub-claims.
The features and advantages of the invention are hereinafter clarified by the detailed description of a preferred embodiment of the invention, with reference to the accompanying drawings, in which:

Fig. 1 is a side view in a vertical section I-I, of a printer apparatus provided with an unrolling group according to the invention;
Fig. 2 is a rear view along section II-II of an unrolling group according to the invention; and
Fig. 3 shows a view of a portion of the unrolling group.

With reference to the drawings, the unrolling group for fabric printer apparatus according to the invention is generally identified by reference numeral 1.
It is adapted to be used for unrolling a reel 10, i.e. a continuous tape of fabric 10a, paper or other similar material rolled up on a cylindrical support so as to enable a working operation such as printing, cutting and folding to be carried out.
In particular, the unrolling group 1 is part of a printer apparatus 100, preferably of the inkjet type, and allows a reel 20 of either synthetic fabric 10a, polyester or Lycra^® for example, or natural fabric such as cotton or linen, to be unrolled so as to arrange it on a conveyor belt 1a adapted to bring the fabric 10a in correspondence with a printer (not shown).
The unrolling group 1 comprises a supporting structure 20 adapted to support the components of the unrolling group 1 and enable arrangement thereof on a rest surface 1b, a floor for example; an unrolling unit 30 adapted to support and unroll reel 10 through rotation about an unrolling axis 30a and defining an advancing or feeding direction; and an extending apparatus 40 adapted to stretch out the fabric 10a coming out of reel 10 so as to enable working thereof in the subsequent printing unit.
The supporting structure 20 comprises two side plates 21 disposed almost perpendicular to the rest surface 1b and mutually connected by tie-rods 22, section bars or other similar structural elements adapted to provide steadiness to the supporting structure 20 and, consequently, the unrolling group 1.
In addition, structure 20 has a plurality of feet 23 between the side plates 21 and rest surface 1 b, which feet are characterised by an adjustable height so as to dispose the unrolling axis 30a substantially parallel to the rest surface 1b. The unrolling group 1 comprises the unrolling unit 30 and extending apparatus 40 suitably connected to the supporting structure 20.
The unrolling unit 30 comprises a cylinder 31 adapted to support reel 10 and defining the unrolling axis 30a.
In particular, to avoid translation of the reel 10 along axis 30a and make it integral with cylinder 31, the cylinder 31 is an expandable cylinder, preferably of the pneumatic type, i.e. adapted to expand following increase of the inner pressure. Alternatively, said reel translation can be prevented by stops adapted to abut against reel 10, thereby preventing translations thereof along substantially the unrolling axis 30a.
In addition, a motor 32 can be provided, usually of the electric type, adapted to operate unrolling of reel 10 through rotation of cylinder 31 and, therefore, of reel 10 around the unrolling axis 30a.
After the unrolling unit 30, in the advancing direction 10a, the unrolling group 1 shows the extending apparatus 40.
This extending apparatus 40 comprises one or more rollers/cylinders connected in a motion-admitting manner to structure 20 so as to rotate, preferably idly, around axes substantially parallel to the unrolling axis 30a and, therefore stretch out the fabric 10 unwound from reel 10; a take-up member 41 defining a sliding surface 41b for the fabric 10a. In particular, the extending apparatus 40 has first rollers 42 and second rollers 43 disposed before and after member 41 respectively, in the fabric advancing direction, as shown in Fig. 1.
The take-up member 41 defines a sliding surface 41 b of the arched type the concavity of which preferably faces belt 1a. It is suitably disposed in such a manner that the sliding surface 41 b is substantially included between the unrolling axis 30a, belonging to the unrolling unit 30, and the rotation axis of the last one of the first rollers 42 that is faced by the fabric 10a before reaching the take-up member 41 itself.
The take-up member 41 comprises a plate 44 defining the sliding surface 42b; one or more stiffening elements 45 comprising plates or other similar elements adapted to give plate 44 appropriate steadiness. Preferably, as shown in Fig. 1, plate 44 is of the faceted type and therefore defines a sliding surface 41 b of the polygonal type.
As an alternative to plate 44, the take-up member 41 can contemplate the presence of a plurality of rollers or other rolling elements having rotation axes substantially parallel to each other and such disposed as to define a sliding surface 41 b of the arched type, the concavity of which faces belt 1a, i.e. a surface similar to that defined by plate 44.
In addition to said elements, the take-up member 41 advantageously comprises a constraint 46 adapted to engage the take-up member 41 with said supporting structure 20 in a motion-admitting manner, i.e. to connect member 41 to structure 20 enabling the take-up member 41 to oscillate relative to structure 20 around an oscillation axis 41a non parallel and transverse to the unrolling axis 30a.
In particular, the oscillation axis 41 lies in a plane substantially perpendicular to the unrolling axis 30a and still more particularly, it is substantially perpendicular to the unrolling axis 30a and lies in the centre of gravity plane, i.e. the plane substantially passing through the centre of gravity of the take-up member 41. Constraint 46 fastens the take-up member 41 to one of the tie-rods 22 and can be identified by a turning joint, i.e. a joint restricting the relative motion of member 41 with respect to the rest of group 1 to a single rotation or, alternatively, by a ball joint i.e. a joint restricting said relative motion to a rotation with respect to a material point defined by the ball joint itself.
In detail, constraint 46, when it is a ball joint as in the illustrated example, has a sleeve 46a integral with a tie-rod 22; a pin 46b defining the oscillation axis 41 a and rigidly and fixedly connected to plate 44 through a stiffening element 45; and bearings 46c, bushes or other similar elements adapted to fasten sleeve 46a in a motion-admitting manner to pin 46b so as to enable the pin 46b and sleeve 46a to mutually rotate around the oscillation axis 41 a.
In the example shown, in order to make the take-up member 41 steadier, it comprises at least one carriage 47 adapted to slide in a sliding plane 47a substantially parallel to the unrolling axis 30a and, preferably, perpendicular to the oscillation axis 41 a. In particular, as shown in Fig. 2, the take-up member 41 comprises two carriages 47 disposed at the side ends of the take-up member 41 while constraint 46 is disposed between the two carriages 47 preferably at a position spaced apart the same distance from carriages 47.
Carriages 47 comprise a base body 47b, rigidly and fixedly connected to member 41 and one or more contact bodies 47c, wheels for example, resting on a support 24 rigidly connected to a tie-rod 22 and defining the sliding plane 47a. In particular, extension of support 24 enables oscillation of the take-up member 41 around the oscillation axis 41 a of a width substantially smaller than 15° and preferably substantially smaller than 10°.
Finally, in order to ensure the correct tension to the fabric 10a during working and, if necessary, vary the value thereof, the extending apparatus 40 comprises at least one dancer adapted to move a first mobile roll 42a suitably along a substantially vertical direction, i.e. perpendicular to the rest surface 1 b.
Each dancer 43 comprises a guide 48a defining a straight movement way; a carriage 48b adapted to slide along the guide and connected to the first mobile roller 42a; two pulleys 48c or gears; a driving belt/chain 48d connected to the first mobile roller 42a and stretched between the two pulleys 48 or gears; and an encoder or other similar mechanism adapted to set the pulleys 48c in motion so as to adjust and substantially maintain tensioning of fabric 10a.
As an alternative to the encoder, two stop limits can be provided which can be identified by a pinion provided with a cam operating inversion of the translation motion of the first movable roller 42a. In a further alternative, two photoelectric cells adapted to read translation of the first roller 42a can be provided.
The unrolling group carries out an innovative printing process for a fabric 10a. The printing process contemplates, in a manner known by itself, a preparation step in which the reel 10 is fastened to the unrolling unit 30; an unrolling step in which reel 10, by rotating around the unrolling axis 30a, is unwound; an extension step in which the fabric is laid down; and a working step in which the fabric 10a reaches belt 1 a and therefore is brought to the printing unit.
The extension step, performed by the unrolling group 1, originally comprises a take-up sub-step in which the fabric 10a is guided around an oscillation axis 41 a transverse to the unrolling axis 30a. It further contemplates a first and a second tensioning sub-steps adapted to stretch the fabric out and carried out before and after the take-up sub-step respectively.
In detail, in the first tensioning sub-step the fabric 10a reaches the first rollers 42 that, due both to their arrangement and to the presence of dancer 40, make the fabric 10a taut.
The fabric 10a goes on advancing and goes beyond the first rollers 42 thus completing the first tensioning sub-step; then it slides along the sliding surface 41 b starting the take-up sub-step.
In particular, during the take-up sub-step, if the fabric 10a shows unevenness and/or defects, it appears that the tension acting on the fabric is not evenly distributed and consequently the fabric 10a imposes a rotation around the oscillation axis 41 a to the take-up member 41.
For instance, if the fabric 10a has an uneven form and, in detail, one of the side edges, i.e. the edges parallel to the advancing direction, is more extended than the other, it exerts a non-perfectly distributed force on the take-up member that will give rise to the presence of a rotational moment relative to the oscillation axis 41 a and acting on the member 41 itself.
This rotation moment therefore imposes oscillation of the take-up member 41 and the fabric 10a laid down thereon relative to axis 41 a and, simultaneously, translation of carriages 47 in the sliding plane 47a.
This oscillation, due to the arrangement of the take-up member 41 between the first and second rollers, causes re-distribution of the tensions acting on fabric 10a and the take-up member 41 until a balance position is reached to which the even distribution of the fabric 10a tensioning corresponds and therefore optimal stretching out of the fabric 10a itself.
The fabric portion 10a encounters the second rollers 43 where the second tensioning sub-step occurs.
The invention achieves important advantages.
A first advantage is represented by the fact that, in spite of the presence of serious defects, such as the inexact sizing of fabric 10a, the unrolling group 1 enables fabric 10a to be always perfectly taut and stretched out and therefore devoid of creases or gathering effects that usually deteriorate printing in known printers.
In particular, the unrolling group 41 allows any fabric 10a to reach the printer in a perfectly extended condition, irrespective of the presence of faults.
For instance, due to the particular operation of the take-up member, described in the take-up sub-step, the unrolling group 1 allows the fabric 10a to reach the printer perfectly taut even if during the manufacturing step it appears with errors (creases/pleats) or is not perfectly squared and therefore is of uneven shape, with side edges non parallel to each other, or a side edge more extended than the other.
This advantage has been reached due to the innovative take-up member 41 and, in particular, the constraint 46 that, defining the oscillation axis 41 a, enables provision of a tilting take-up member 41 which is therefore adapted to rotate about the oscillation axis 41 a so as to evenly re-distribute the tensions acting on the fabric 10a, thereby ensuring perfect stretching out of the fabric 10a itself, regardless of the presence of size defects therein.
This effect has been further increased by the fact that the second axis 31 a, substantially lying in the diametral plane, causes a further more even distribution of the tensions along the fabric 10a.
Another advantage is therefore represented by the fact that the printer apparatus 100 and, in detail, group 1 allows printing of high quality and accuracy to be obtained giving rise to a production almost devoid of rejects.
A further advantage is represented by the fact that the unrolling group 1 is able to reach high production rates and simultaneously high printing quality, as compared with known groups.
In fact, due to the fact that the unrolling group 1 enables fabric 10a, regardless of the defects present therein, to be always perfectly taut and therefore able to define an optimal printing surface, the unrolling group 1 is suitable to unroll reel 10 more quickly so that a greater amount of fabric 10a can reach the printer.

Claims

An unrolling group (1) for fabric (10a) printer apparatus (100) comprising a supporting structure (20) adapted to enable said unrolling group (1) to be disposed on a rest surface (1 b); an unrolling unit (30) adapted to support a reel (10) of said fabric (10a), so as to enable said reel (10a) to be unrolled through rotation about an unrolling axis (30a); an extending apparatus (40) adapted to tension said fabric (10a) coming from said reel (10); and characterised in that said extending apparatus (40) comprises a take-up member (41) defining a sliding surface (41) for said fabric (10a) and comprising a constraint (46) adapted to connect said take-up member (41) in a motion-admitting manner to said supporting structure (20) so as to enable said take-up member (41) to oscillate relative to an oscillation axis (41a) transverse to said unrolling axis (30a).
An unrolling group (1) as claimed in claim 1, wherein said oscillation axis (41 a) lies in a plane substantially perpendicular to said unrolling axis (30a).
An unrolling group (1) as claimed in the preceding claim, wherein said oscillation axis (41 a) lies in a centre of gravity plane substantially passing through the centre of gravity of said take-up member (41) and substantially perpendicular to said unrolling axis (30a).
An unrolling group (1) as claimed in the preceding claim, wherein said oscillation axis (41a) is substantially perpendicular to said unrolling axis (30a) and rest surface (1 b).
An unrolling group (1) as claimed in one or more of the preceding claims, wherein said extending apparatus (40) comprises first rollers (42) and second rollers (43) disposed in the advancing direction of said fabric (10a), before and after said take-up roller (41), respectively.
An unrolling group (1) as claimed in one or more of the preceding claims, wherein said take-up member (41) comprises at least one carriage (47) adapted to slide along said supporting structure (20) in a sliding plane (47a) substantially perpendicular to said oscillation axis (41 a).
An unrolling group (1) as claimed in the preceding claim, wherein said sliding plane (47a) is substantially parallel to said rest surface (1 b).
An unrolling group (1) as claimed in one or more of claims 5-6, wherein said take-up member (41) comprises two of said at least one carriage (47), and wherein said constraint (46) is disposed between said two carriages (47).
An unrolling group (1) as claimed in the preceding claim, wherein said constraint (46) is disposed at a position substantially spaced apart the same distance from said two carriages (47).
An unrolling group (1) as claimed in one or more of the preceding claims, wherein said constraint (46) is a turning joint.
An unrolling group (1) as claimed in one or more of the preceding claims, wherein said constraint (46) is a ball joint.
A fabric (10a) printer apparatus (100) comprising an unrolling group (1) as claimed in one or more of the preceding claims.
A printing process for a fabric comprising an unrolling step in which said fabric (10a) is unrolled from a reel rotating about an unrolling axis (30a); an extending step in which said fabric (10a) is tensioned and stretched out; and characterised in that said extending step comprises a take-up sub-step in which said fabric (10a) is at least partly oscillated about an oscillation axis (41 a) transverse to said unrolling axis (30a).
A printing process as claimed in the preceding claim, wherein said extending step comprises two tensioning sub-steps and in which said take-up sub-step is interposed between said tensioning sub-steps.