Digital printing and finishing method for fabrics and the like

Abstract

A method of digital printing and finishing for fabrics is provided. The method includes a step of unwinding a fabric from a first reel. A step of compensating the speeds and of spreading the fabric for its positioning on a conveyor belt provided with supporting elements on which a digital printing step occurs is provided. A step of drying the fabric is provided. A step of winding the fabric onto a second reel is provided. These steps are being executed at corresponding stations arranged in sequence with respect to each other and the fabric passing through them continuously, transversely to the conveyor belt, there being a plurality of bars provided with printing heads which are controlled electronically and synchronized with the movement of the conveyor belt.

Description

TECHNICAL FIELD

The present invention relates to a digital printing and finishing method for fabrics and the like.

BACKGROUND ART

The conventional method of digital printing and finishing for fabrics, starting with a fabric for conventional printing that has previously been rendered hydrophilic in order to allow the penetration of conventional printing pastes, is made up of a sequence of steps that are executed independently of each other.

More precisely, this sequence consists in a step of preparing the fabric for digital printing, in which the fabric for conventional printing is impregnated with adapted substances in order to enable the fixing of the color in order to subsequently be dried, a printing step, in which the fabric is printed and dried, a steaming step, in which the fabric is placed in a steaming chamber for a period that can vary from ten to thirty minutes according to the type of fabric and to the type of printing ink used, a washing step, in which the fabric is washed to remove excess quantities of ink, and a drying step, in which the fabric is dried.

This conventional method suffers the drawback of displaying limited productivity because of the fact that the individual steps occur independently of each other.

In order to speed up the method of printing, a known technique is to have the washing and drying steps occur continuously. This attempt at speeding the method up is however not sufficient to adequately reduce the processing times.

DISCLOSURE OF THE INVENTION

The aim of the present invention consists in providing a method of digital printing and finishing for fabrics that is faster than the conventional method of digital printing and finishing, while increasing the productivity of the system.

Within this aim, an object of the present invention consists in providing a method of digital printing and finishing for fabrics that is simple and effective, while at the same time ensuring low costs of implementing the system and production costs that are economically advantageous when compared to those of the known art.

Another object of the present invention is to provide a method of digital printing and finishing for fabrics that limits manual intervention from the operator as far as possible.

Another object of the present invention is to provide a method of digital printing and finishing for fabrics that, thanks to its peculiar implementation characteristics, is capable of offering the widest guarantees of reliability and safety in use.

This aim and these and other objects which will become better apparent hereinafter, are achieved by a method for printing and finishing for fabrics and the like, characterized in that it comprises a step of unwinding a fabric from a first reel, a step of compensating the speeds and of spreading said fabric in order to position it on a conveyor belt provided with supporting means on which a digital printing step occurs, followed by a step of drying said fabric and a step of winding said fabric onto a second reel, said steps being performed in corresponding stations arranged in sequence with respect to each other and said fabric passing through said stations continuously, transversely to said conveyor belt there being a plurality of bars provided with printing heads which are controlled electronically and synchronized with the movement of said conveyor belt.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the invention will become better apparent from the detailed description of two preferred, but not exclusive, embodiments of a method of printing and finishing for fabrics and the like, which are illustrated by way of non-limiting example in the accompanying drawings, wherein:

FIG. 1 is a schematic side elevation view of a system according to a first embodiment of a method of printing and finishing for fabrics and the like, according to the present invention;

FIG. 2 is an enlarged-scale detailed view of the station corresponding to the printing step of the system shown in FIG. 1;

FIG. 3 is a schematic plan view from above of the station shown in FIG. 2;

FIG. 4 is a schematic side elevation view of a system according to a second embodiment of a method of printing and finishing for fabrics and the like, according to the present invention.

WAYS OF CARRYING OUT THE INVENTION

With reference to the figures, the first embodiment of the method of printing and finishing for fabrics and the like, according to the invention, is performed by a system, generally designated in FIG. 1 by the reference numeral 1a, and comprises a step of unwinding a fabric 2 from a first reel 3, a step of compensating the speeds and of spreading the fabric 2 in an adapted station 4 for positioning it on a conveyor belt 5 provided with supporting means, for example of the adhesive type, on which a digital printing step occurs.

Advantageously, transversely to the conveyor belt 5, there is a plurality of bars 6 provided with printing heads 7 which are controlled electronically and synchronized with the movement of the conveyor belt 5.

More precisely, the printing heads 7 are of the piezoelectric ink jet type and are positioned on each one of the bars 6 in such a manner as to cover the width of the conveyor belt 5 and allow continuous printing.

Subsequently a step of drying the fabric 2 and a step of winding it onto a second reel 11 are provided. This drying step can occur with hot air in a steaming chamber 12 or the like.

Differently, in the second embodiment, for which the corresponding system 1b is shown in FIG. 4 between the unwinding station and the printing station a step can be provided of immersion of the fabric 2 unwound from the first reel 3 in a tank 8 containing an aqueous solution 9 comprising at least one or more substances selected from the group constituted by pH stabilization compounds and salts adapted to facilitate the fixing of the ink on the fabric 2 in the subsequent steaming step described below.

Conveniently, following the above mentioned immersion, a step is provided of pressing the fabric 2 impregnated with the aqueous solution 9 through a pair of presser rollers 10 in such a manner as to eliminate the excess part of the aqueous solution 9 from the fibers of the fabric 2.

Following the digital printing step, a step is provided of steaming the fabric 2 printed and impregnated with the aqueous solution 9 through a steaming chamber 12 in such a manner as to fix the ink to the fabric 2.

In this step, the fabric 2 retains a level of humidity similar to that of the previous steps and, given the speed at which this step occurs, which is comprised between 1 and 100 meters per minute, is such as to accelerate the process of penetration of the color into the fibers of the fabric 2.

Moreover, thanks to a steam temperature that is adapted to the process under conditions of atmospheric pressure, it is sufficient for the fabric 2 to remain in the steaming chamber 12 for 10 to 40 seconds in order to obtain the required fixing.

Conveniently, the steaming chamber 12 is dimensioned as a function of the top speed of the printing step, so as to ensure that the fabric 2 remains inside the steaming chamber 12 for a sufficient time.

Thereafter, a step can be provided of washing the printed and steamed fabric 2 which is adapted to eliminate from the fabric 2 the excess part of the ink by means of immersion in an adapted tank 13.

The fabric 2 is then dried and brought back to its initial size through two adapted machines 14 and 15 or it is simply dried and subsequently rewound onto the reel 11.

To sum up, in both of the proposed embodiments, the method according to the invention comprises a sequence of steps performed in corresponding stations arranged in sequence with respect to each other with the fabric 2 passing through all of them continuously.

More precisely, with regard to the first embodiment, the continuous method of digital printing and finishing, according to the invention, is adapted, for example, to fabrics printed with acid or disperse inks and, with regard to the second embodiment, the continuous method of digital printing and finishing, according to the invention, is adapted, for example, to fabrics printed with reactive inks such as monochloro/dichloro triazine and vinyl sulfone.

In practice it has been found that the method of digital printing and finishing for fabrics and the like, according to the present invention, achieves the intended aim and objects in that it is much faster than the conventional methods of digital printing.

Another advantage of the method, according to the present invention, consists in that it enables an energy saving as a result of the reduction of the number of drying processes and the reduction of the evaporation time.

A further advantage of the method, according to the present invention, consists in that, thanks to the continuity of the process, the movement is eliminated of the fabric between the several necessary steps to obtain the required product.

The method of printing and finishing for fabrics and the like thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims.

For example, instead of having the fabric on reels both in input and in output, it can be arranged in sheets.

Moreover, all the details may be substituted by other, technically equivalent elements.

In practice the materials employed, provided they are compatible with the specific use, and the contingent dimensions and shapes, may be any according to requirements.

The disclosures in Italian Patent Application No. MI2010A002176 from which this application claims priority are incorporated herein by reference.

Claims

1. A method of digital printing fabrics, the method comprising: supplying a fabric from a first reel by unwinding,applying an ink-fixing solution to the supplied fabric,compensating a speed of a conveyor belt with a speed of the fabric unwound from the first reel;adhering the fabric to the conveyor belt,with the fabric adhered to the conveyor belt, digitally printing an ink onto the fabric using a plurality of bars transversally extending above the conveyor belt and provided with ink-jet printing heads, while continuously moving the conveyor belt and electronically controlling the printing heads and synchronizing the printing heads with movement of the conveyor belt, thereby allowing continuous printing,drying the fabric, and thenwinding the dried fabric onto a second reel or arranging the dried fabric in sheets;wherein the above steps are performed in corresponding stations arranged in sequence while the fabric is continuously passing through the stations.

2. The method of claim 1, wherein applying the ink-fixing solution comprises impregnating with the ink-fixing solution fibers of fabric unwound from the first reel before the unwound fabric reaches the conveyor belt.

3. The method of claim 2, wherein the step of digitally printing comprises digitally printing fibers of the fabric impregnated with the ink-fixing solution.

4. The method of claim 3, wherein applying the ink-fixing solution comprises immersing fabric unwound from the first reel in a tank containing the ink-fixing solution.

5. The method of claim 1, further comprising eliminating excess ink-fixing solution from the fibers of the fabric before digitally printing the fabric.

6. The method of claim 1, further comprising fixing the ink on the printed fabric between the digital printing and the drying.

7. The method of claim 6, fixing the ink comprises steaming the printed fabric in a steaming chamber.

8. The method of claim 7, comprising a step of washing said printed and steamed fabric to eliminate from said fabric excess part of said ink, said washing step being comprised between said steaming step and said drying step.

9. The method of claim 7, wherein steaming the printed fabric comprises keeping the steaming chamber at atmospheric pressure conditions and maintaining the fabric in the steaming chamber for 10 to 40 seconds.

10. The method of claim 6, further comprising washing the printed fabric to remove excess ink between the ink fixing and the drying.

11. The method of claim 1, wherein applying the ink-fixing solution to the fabric occurs between the unwinding and the speed compensation.

12. The method of claim 1, wherein adhering the fabric to the conveyor belt comprises adhesively adhering the fabric to the conveyor belt.

13. The method of claim 1, wherein the printing heads are arranged on each one of said bars in such a manner as to cover the width of said conveyor belt.

14. The method of claim 1, wherein the ink-fixing solution is an aqueous ink-fixing solution.

15. The method of claim 14, wherein the aqueous ink-fixing solution comprises pH stabilization compounds pH stabilization salts or mixtures thereof.

16. The method of claim 1, wherein digitally printing the fabric comprises applying reactive inks.

17. A method of digital printing fabrics, the method comprising: supplying a fabric from a first reel by unwinding,applying an ink-fixing solution comprising a pH stabilizer to the fabric by impregnating,compensating a speed of a conveyor belt with a speed of the fabric unwound from the first reel;adhering the fabric to the conveyor belt,while the fabric is adhered to the conveyor belt, digitally printing the adhered fabric using a plurality of bars transversally extending above the conveyor belt and provided with ink-jet printing heads while continuously moving the conveyor belt and electronically controlling the printing heads and synchronizing the printing heads with movement of the conveyor belt, wherein the digitally printing includes digitally printing fibers of the fabric impregnated with the ink fixing solution with reactive ink,steaming the printed fabric through a steaming chamber to fix the ink to the fabric,drying the steamed fabric, andwinding the dried fabric onto a second reel or arranging the dried fabric in sheets;wherein the above steps are performed in corresponding stations arranged in sequence while the fabric is continuously passing through the stations.

18. A method of digital printing fabrics comprising the following sequence of steps: supplying a fabric from a first reel by unwinding,applying an aqueous ink-fixing solution comprising a pH stabilizer to the fabric by impregnating,compensating a speed of a conveyor belt with a speed of the fabric unwound from the first reel;adhering the fabric to the conveyor belt,while the fabric is adhered to the conveyor belt, digitally printing the fabric using a plurality of bars transversally extending above the conveyor belt and provided with ink-jet printing heads while continuously moving the conveyor belt and electronically controlling the printing heads and synchronizing the printing heads with movement of the conveyor belt, wherein the digitally printing includes digitally printing fibers of the fabric impregnated with the ink fixing solution with reactive ink,drying the printed fabric, andwinding the dried fabric onto a second reel or arranging the dried fabric in sheets;wherein the above steps are performed in corresponding stations arranged in sequence while the fabric is continuously passing through the stations.