Uitspraken

De conclusies van EP 159 luiden, in de originele Engelse taal:

“1. A digital printing and finishing method for fabrics and the like, comprising:

a step of unwinding a fabric (2) from a first reel (3),

a step of compensating the speeds and of spreading said fabric (2) in order to position it on a conveyor belt (5) provided with supporting means on which a digital printing step occurs, followed by a step of drying said fabric (2), and a step of winding said fabric (2) onto a second reel (11) or of arranging said fabric (2) in sheets, said steps being performed in corresponding stations arranged in sequence with respect to each other and said fabric (2) passing through said stations continuously, transversely to said conveyor belt (5) there being a plurality of bars (6) provided with printing heads (7) which are controlled electronically and synchronized with the movement of said conveyor belt (5).

De – niet bestreden – Nederlandse vertaling van de conclusies is hierna weergegeven:

“1. Een werkwijze voor het digitaal bedrukken en het afwerken voor stoffen en dergelijke, omvattend:

een stap van het afwikkelen van een stof (2) van een eerste spoel (3),

een stap van het compenseren van de snelheden en van het uitspreiden van de stof (2) om deze te positioneren op een transportband (5), voorzien met steunmiddelen waarop een stap van digitaal drukken plaatsvindt,

gevolgd door de stap van het drogen van de stof (2), en een stap van het wikkelen van de stof (2) op een tweede spoel (11) of van het inrichten van de stof (2) in lagen,

waarbij de stappen worden uitgevoerd in overeenkomstige stations die zijn ingericht in opvolging met betrekking tot elkaar en waarbij de stof (2) continu door de stations gaat, waarbij er transversaal tot de transportband 5) een veelheid aan stangen (6) is, voorzien met printkoppen (7) die elektronisch worden gestuurd en worden gesynchroniseerd met de beweging van de transportband (5).

“ Technical Field

[0001] The present invention relates to a digital printing and finishing method for fabrics and the like.

Background art

[0002] 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.

[0003] 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.

[0004] This conventional method suffers the drawback of displaying limited productivity because of the fact that the individual steps occur independently of each other.

[0005] 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.

(…)

[0007] Document WO2009/102208A1 discloses an apparatus for printing a web of material by means of ink jet heads; a conveyor belt driven at constant speed transports a textile web to the inkjet heads and removing means act to catch and remove floating ink droplets; the

inkjet heads are energized in relation to the chosen set speed of the conveyor belt and the mutual distances in the direction of transport between successive inkjet heads.

Disclosure of the invention

[0008] 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.

[0009] 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.

[0010] 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.

[0011] 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.

[0012] 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, according to claim 1.

Brief description of the drawings

[0013] 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:

Figure 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;

(…)

Figure 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

[0014] 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 Figure 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.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] Differently, in the second embodiment, for which the corresponding system 1b is shown in Figure 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.

(…)

[0026] 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.

(…)

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] For example, instead of having the fabric on reels both in input and in output, it can be arranged in sheets.”

Tot de stand van de techniek behoort de Europese octrooiaanvrage EP 1 591 258 A1 voor “Apparatus for printing a textile web” gepubliceerd op 2 november 2005, aangevraagd door Osiris Technology B.V. op 29 april 2004 (hierna: de Osiris-aanvrage). De Osiris-aanvrage openbaart een (digitale) inkjetdrukmachine in, onder meer, claim 1:

“1. Apparatus for printing a web of textile, which apparatus comprises:

a main frame;

an endless conveyor belt which is guided over a driven roller and a reversing roller disposed substantially parallel thereto and which is driven by motor means at a chosen constant speed;

glue dispensing means for applying a glue layer upstream of the active upper part of the conveyor belt for temporary light adhesion of the textile web to this active part such that this web is fixed non-movably relative to the conveyor belt;

optional washing means placed downstream relative to the active part for removing the glue from the conveyor belt;

supply and feed means for feeding a textile web from a supply to the active part of the conveyor belt;

printing means for printing the passing textile web in the zone of the active part of the conveyor belt in a number of colours in accordance with an adjustable pattern for selecting; and discharge and storage means for removing the printed textile web from the conveyor belt and subsequent storage thereof;

characterized in that

the printing means comprise a number of, for instance 2-8, frame beams extending in transverse direction above said active part at determined mutual longitudinal distances along the direction of transport, each of which frame beams carries an array of inkjet heads and each of which is immobile during operation relative to the plane defined by the active part;

control means are present which fulfil at least the following functions of:

storing a chosen printing pattern by means of inputting pattern information, for instance from a scanner;

energizing the inkjet heads, also in relation to the chosen set speed of the conveyor belt and the mutual distances in the direction of transport between successive inkjet heads for the respective colours, such that each head sprays droplets of ink of the relevant colour onto the web at the positions on the web determined by the control means;

the discharge means comprise drying means for drying the ink applied to the textile web.”

De beschrijving van de Osiris-aanvrage bevat onder meer de volgende passages:

“[0004] The invention has for its object to obviate said drawbacks of the prior art. It is a particular object of the invention to provide an apparatus which enables a printing accuracy of about 10 μm while making use of provisions which allow a very rapid change-over to other patterns without any substantial loss of usable coloured ink.

[0005] In respect of the above stated objectives, the apparatus according to the invention has the feature that the printing means comprise a number of (…) frame beams extending in transverse direction above said active part at determined mutual longitudinal distances along the direction of transport, each of which frame beams carries an array of inkjet heads and each of which is immobile during operation relative to the plane defined by the active part;

control means are present which fulfil at least the following functions of:

(…)

energizing the inkjet heads, also in relation to the chosen set speed of the conveyor belt and the mutual distances in the direction of transport between successive inkjet heads for the respective colours, such that each head sprays droplets of ink of the relevant colour onto the web at the positions on the web determined by the control means;

(…)

[0006] It should be understood that according to the invention the textile web is guided at a fixed speed through the apparatus and that the inkjet heads used are in wholly stationary position.

[0007] Intermittent driving of the endless conveyor belt could be envisaged such that by making use of movable inkjet heads a temporarily stationary surface for printing is printed by the inkjet heads, followed by a stepwise further transport of the conveyor belt so that a subsequent part of the textile web can be printed in the same manner.

[0008] Such a technical embodiment is seen as being very disadvantageous according to the invention in respect of the very complicated controls required, the acceleration forces which occur and the positioning errors inherent to such a system, these being manifested in a poorer printing quality.

[0009] The apparatus according to the invention on the other hand makes use of only one moving component, i.e. the endless conveyor belt, which ensures that the textile web for printing is guided through the apparatus at a very precisely controlled fixed speed.

[0010] The inkjet beams, which each correspond with a preselected colour, lie at a mutual distance which can be determined by the control unit by means of a simple calibration process such that the determined mutual distances can be taken into account in the calculation of the correct times for energizing the inkjet heads. The mechanical problems of the above described prior art and a possible other solution on the basis of inkjet printing are thus wholly resolved according to the invention by making use of a very simple but very precise and stable mechanical setup with only one drive and a powerful computer system in co-action with very high-quality inkjet heads (…)”

De cijfers bovenaan figuur 2 verwijzen naar verschillende functionele onderdelen van het apparaat, te weten een ‘infeed unit’ (13), een ‘printing unit’ (16), een ‘dryer’ (25) en een ‘discharge and storage unit’ (26).

Tot de algemene vakkennis van de gemiddelde vakman op de prioriteitsdatum behoort onder meer het handboek Encyclopedia of Textile Finishing van Prof. H-K Rouette uit 2001(hierna: Rouette). Op pagina 161 van die encyclopedie zijn de volgende definities en bijbehorende figuur opgenomen:

“Compensator roll device Device for regulating uniform fabric run and fabric speed or machine elements by raising and lowering motions. If two machines arranged in series (e.g. in continuous woven fabric pretreatment) need to be synchronised (Fig.), a compensator

roller (or an identically functioning dancer roller as an alternative) is located between the machines.

The compensator roller motion is transmitted to the actual value sensor via a chain drive with a transmission ratio of iK. The angle of deflection ϕ on the actual value sensor is therefore defined as the controlled variable.

Fig.: Compensator roll device for the synchronisation of two machines arranged in series.

A potentiometer, the terminal voltage of which illustrates the compensator roller angle in analogue terms, serves as a measured value transducer. One possibility of affecting the speed of the fixed traction roller, and therefore the fabric speed, is to change the transmission ratio of the steplessly adjustable PIV gear by servomotor. Changing the transmission ratio is possible via the axial displacement of the two bevel wheel pairs.

Another possibility is to transmit the potentiometer setting via appropriate pulses to the DC motor (with variable speed via the voltage) or to an alternative AC motor with frequency control in order to let a machine run faster or slower. In this closed control circuit therefore

– the fabric is the controlled member,

– the compensator roller is the sensor,

– the drive to the rear machine is the actuator,

– the speed of the first machine is the reference value, to which the actual value of the second machine “lines up” via the compensator roll.

Compensator roller (dancing roller). Roller which moves up and down on movable bearings for equalising the tension on open-width piece goods between continuous operation finishing machines.”

in reconventie