ES2929249B2 - Suction system for digital inkjet printers and corresponding digital inkjet printer - Google Patents

Description

DESCRIPTION

Suction system for digital inkjet printers and corresponding digital inkjet printer

field of invention

The present invention relates to the field of digital inkjet printers for plates, preferably ceramic or glass plates or other material (such as wood or other).

More specifically, the present invention relates to a suction system for digital inkjet plate printers.

state of the art

As is known, digital inkjet printers require certain measures to improve print quality and maintain printer functionality and efficiency.

In particular, it is known to use suction and/or cleaning systems that involve the use of suction hoods located on one side (that is, downstream) of each color bar of the printer to suck the ink vapors generated by the ink dispensing from the print heads of each color bar while the machine is running.

In addition, it is also known to use one or more suction carriages which, during programmed machine stoppage periods, suck up the ink drops which, during use, are deposited on the print head heads.

A need in the sector is to improve the suction capacity of the suction hoods and, therefore, improve the quality of the print.

In particular, a need in the sector is to reduce the possibility of altering the trajectory of the ink drops thrown from the print heads onto the plate due to the turbulence of the suction airflow caused by the suction hoods and, at the same time, make the aspiration efficient and therefore reduce the amount of ink mist (i.e. ink vapors) in the volume between the print heads and the plate to be printed, which can dirty the plates or the printing environment.

Description of the invention

One objective of the present invention is to satisfy the mentioned needs of known technology and other needs that will be better described below, within the framework of a simple, rational and low-cost solution.

These objectives are achieved thanks to the features of the invention set forth in the independent claims. The dependent claims describe preferred and/or particularly advantageous aspects of the invention.

The invention, in particular, provides a suction system for a digital inkjet printer for plates, wherein the digital inkjet printer is provided with a plurality of color bars, each of which is provided with at least one set of inkjet print heads, in which the aspiration system comprises:

a suction device;

a plurality of suction tubes, including at least one for each color bar of the digital printer, wherein the suction tubes are connected to the suction device and are arranged with longitudinal axes parallel to each other and parallel to the longitudinal axes of the colored bars, wherein the suction tubes of the plurality of suction tubes are connected to each other in parallel;

a plurality of capacity control devices, each of which is connected to a respective suction tube, in order to regulate the suction power of the respective suction tube.

Thanks to this solution, it is possible to divide the suction air flow of each suction tube independently from the others, which allows the variation of the suction conditions depending on the printing conditions of each color bar.

Advantageously, the suction system can comprise a control unit electronic operatively connected to each partitioning device.

Preferably, the electronic control unit may be configured to:

determining a value of a parameter indicative of the volume of ink that is dispensed from each color bar for making a decoration on at least one plate;

determining a value of a suction power for each suction tube based on the value of the determined indicative parameter; and

Check each capacity control device so that it works with the determined suction power value.

Thanks to this solution, the variation of the suction conditions of each suction tube can be done in a dynamic and controlled manner, depending on the contingent printing conditions of each color bar.

Advantageously, the electronic control unit can be operatively connected to the suction device and can be configured to:

determining a maximum value of a suction power based on the determined indicative parameter value; and

control the suction device to generate the value of the total suction power.

Preferably, the electronic control unit (for determining a value of a parameter indicative of the volume of ink that is dispensed from each color bar) may be configured to:

receive an image of the decoration to print it on a plate;

decomposing the image into a plurality of monochrome subimages, each monochrome subimage being combined with a respective color bar to print it on the plate itself;

calculating the value of the parameter indicative of the ink volume based on the monochrome subimage.

In addition, each suction tube can comprise a downwardly oriented longitudinal suction slot that extends along a certain longitudinal section of the suction tube.

Once again, each suction tube can comprise means for varying the suction section of each suction tube along the longitudinal axis of the suction slot.

Thanks to this, it is possible to make the suction uniform along the entire longitudinal development of the suction slot.

Preferably, the variation means can comprise a longitudinal partitioning wall fixed internally to the respective suction tube above the suction slot and means for regulating the inclination of the partitioning wall with respect to the suction slot.

In addition, the suction system can comprise at least one suction carriage arranged with its own longitudinal axis orthogonal to the longitudinal axis of the suction tubes and arranged below at least one colored bar and the respective suction tube, in which the suction carriage is movable in sliding along a sliding direction parallel to the longitudinal axis of the suction tubes.

Thanks to this, the cleaning action exerted by the suction carriage can be optimized by sucking also in correspondence with the suction slot of the suction tubes (where drops of ink can be deposited during the printing phase).

In such a case, the suction carriage may comprise a suction shoe defining an elongated suction slot along the longitudinal axis of the suction carriage itself, in which the suction slot is oriented upwards and the print heads each colored bar and the suction groove of the respective suction tube are superimposed in plan on the suction groove of the suction shoe during sliding of the suction carriage along the direction of sliding.

Furthermore, the suction carriage may comprise a cleaning tab configured to enter the suction groove of the suction tube during sliding of the suction carriage along the direction of sliding.

Thanks to this, possible solid residues, such as dust, pollen or contaminants, that settle in the suction slot of the suction tubes (especially in certain circumstances of use of the printer) can be effectively removed (and sucked by the printer). suction cart).

For the same purposes as above, the invention also provides a digital inkjet printer for plates comprising:

a carrier configured to support at least one plate resting on its own lower surface opposite the upper surface to be decorated;

a plurality of color bars arranged above the conveyor, wherein each color bar is provided with at least one set of ink jet print heads; and

a suction system as described above.

Brief description of the drawings

Other features and advantages of the invention will become apparent from reading the following description provided by way of example and not limiting, with the aid of the figures illustrated in the attached drawings.

Figure 1 is a schematic side view of a printer according to the invention.

Figure 2 is an axonometric view of a detail of the printer of Figure 1.

Figure 3 is a schematic axonometric view of a suction system for a printer according to the invention.

Figure 4 is an exploded view of Figure 3.

Figure 5 is a side view of Figure 3.

Figure 6 is a top view of Figure 3.

Figure 7 is an axonometric view of a detail of the printer of Figure 1, illustrating a cleaning system according to the invention.

Figure 8 is an implementation system of a printer cleaning system according to the invention.

Fig. 9 is a flowchart of a printer vacuum control method according to the invention.

Detailed description of some embodiments of the invention

With particular reference to such figures, indicated globally by numeral 10 is a digital ink-jet printer, for example, of the single-pass type or multi-pass or other, for plates, for example, ceramic plates or glass plates or wooden plates or any other material, indicated globally with the letter S.

The printer 10 is configured to release a decoration or print, according to a predetermined pattern, on a surface of a plate S.

The printer 10 comprises a conveyor 20, which is configured to support at least one plate S which rests on its own lower surface opposite the upper surface to be decorated/printed.

The conveyor 20 comprises a support frame 21 provided with ground supports and a transport unit 22 supported by the support frame 21.

Conveyor unit 22 may be defined by or comprise a conveyor belt of a belt conveyor or a pair of belts of a belt conveyor or other commonly known conveyor.

The transport unit 22 defines a (horizontal) support plane on which the plates S, with their lower surface, are intended to rest (in a stable manner).

The transport unit 22 can additionally be configured to move the plates S that are supported on the support plane along a feed direction A parallel to the support plane itself (i.e. horizontal), for example with a forward speed that can be set and/or regulated based on the needs of the job.

The printer 10 comprises a printing module, schematically indicated with the reference number 30, which is configured to release a predetermined decoration on the upper surface of the plate S that rests on (the support plane of) the transport unit 22 .

The printing module 30 is preferably a digital (ink-jet) printing device, commonly used to print the plates S.

The term decoration generally refers to the application of decorative fluids, such as coloring and/or decorative inks, but also to the application of any product in fluid or liquid or semi-solid form, for example, functional coatings, coatings, protective or anti-reflective layers. or similar.

The printing module 30 is arranged above the support plane of the transport unit 22, for example, at a predetermined (non-zero) distance from it, so that between the printing module 30 and the support plane of the transport unit 22 can insert (with clearance) a plate to be decorated.

The printing module 30 is, for example, movable (by means of a suitable motorization and the respective articulation/guidance systems) between at least one working position, in which it is arranged at a predetermined working distance from the support plane of the transport unit 22, in which, for example, said working distance is (variable by) depending on the thickness of the plates S to be decorated, and at least one rest position, in which it is arranged at a distance of predetermined rest of the support plane of the transport unit 22, in which, for example, said rest distance is greater than the working distance.

For example, the printing module 30 is slidably associated with the (support frame 21 of) the conveyor 20 along a (vertical) sliding direction orthogonal to the support plane, so that it can alternately pass from the position from rest to a working position.

The printing module 30 is arranged, for example, in a central longitudinal area (with respect to the direction of advance A) of the transport unit 22.

The printing module 30 comprises at least one color bar 31, which is configured to release a respective monochrome decoration (part of the predetermined overall decoration) on an upper surface of the plate S (resting on the support plane of the plate). transport unit 22).

In other words, each color bar 31 is preferably configured to dispense a respective ink (or color).

For example, each color bar 31 is elongated along its own longitudinal (horizontal) axis parallel to the supporting plane (at least when the printing module 30 is in its working position), which is, for example, orthogonal to the direction of advance A.

Preferably, the printing module 30 comprises a plurality of color bars 31, one next to the other with respect to a direction of mutual juxtaposition, preferably parallel to the support plane (horizontal) and parallel to the direction of advance A.

Each color bar 31 comprises a box body provided with a lower wall facing the support plane of the conveyor 20, in which a plurality of openings are provided.

The lower walls of the color bars 31 of the printing module 30 are coplanar with each other.

Each color bar 31 comprises at least one inkjet print head 32, preferably a plurality of print heads 32, for example, aligned with each other along an alignment direction parallel to the longitudinal axis of the color bar. 31 and (orthogonal to the direction of mutual apposition of the color bars themselves, ie to the direction of advance A).

Each print head 32 in turn has a longitudinal axis parallel to the longitudinal axis of the color bar 31.

Each color bar 31 comprises a plurality of parallel rows of print heads 32 (for example, two in number), each of which is made up of a plurality of print heads 32 aligned along the direction of alignment, which are, for example, staggered from each other.

The print heads 32 of each color bar 31 may be of any known type without limitation.

Each print head 32 is arranged inside the body of the box of the respective color bar 31, so that it protrudes (without protruding) into a respective opening in the bottom wall thereof.

Each print head 32 is provided with suitable dispensing nozzles (on the bottom wall of the print head 32 facing the opening in the bottom wall of the box body) configured to dispense (in a controlled manner) a decorative fluid, such as such as, for example, an ink, a glaze or the like, which will be dispensed on the upper surface of the plates S that rest on the support plane made available by the transport unit 22.

The dispensing nozzles are actuated to apply the ink to the top surface of the plates S in a controlled manner.

For example, the dispensing nozzles can be of the piezoelectric type, that is, they can comprise a small plate of piezoelectric material (that is, capable of deforming when subjected to an electric current) which, under the action of modulated electrical pulses, determines the dispensing of calibrated ink drops.

For example, each color bar 31 is slidably associated (with respect to the printing module 30), along a withdrawal direction parallel to the longitudinal axis of the color bar itself.

The printer 10 also comprises a suction system collectively indicated by the number 40.

The suction system 40 comprises, for example, a suction device 45, configured to generate a flow of sucked air.

The suction device 45 is, for example, an (industrial) vacuum cleaner.

Preferably, the suction device 45 includes suction power variation means (for example, of the type of an inverter), configured to operate a variation of the suction power generated by the suction device 45, for example, between a maximum value of suction power and a minimum value (for example, zero) of suction power.

For example, the suction device 45 is equipped with an inverter configured to vary the speed of rotation of (an electric motor associated with) an impeller, for example, dynamically.

The variation of the speed of rotation of the impeller is such that it causes the variation of the suction power of the suction device 45.

The suction system 40 comprises a first suction device 50 configured to suck the ink vapors or drops generated by the color bars 31 during printing.

Preferably, the first suction device 50 comprises a plurality of suction tubes 51, at least one of which is provided for each color bar 31 of the printer 10.

The first suction device 50 is rigidly attached to the printing module 30 (for example, integral thereto).

However, the possibility is not excluded that the first suction device 50, that is, each suction tube 51, can be integrally associated (for example, rigidly fixed) to the respective color bar 31, for example, sliding with it along the direction of removal.

Furthermore, it is possible that each suction tube 51 can be individually slidably associated with the printing module 30 with respect to said extraction direction (independent of the respective color bar 31).

Each suction tube 51 extends along a respective longitudinal axis.

The suction tubes 51 are arranged parallel to each other and parallel to the longitudinal axes of the color bars 31.

For example, each draft tube 51 is positioned adjacent to a respective color bar 31, for example upstream and/or downstream (preferably downstream) thereof in the direction of mutual juxtaposition, preferably in the direction forward a.

For example, each color bar 31 is interposed between two suction tubes 51 substantially adjacent to it without discontinuity.

For example, each suction tube 51 comprises a longitudinal suction slot 510 facing downwards, that is, towards the support plane of the conveyor 20.

The suction slot 510 extends, for example, for a certain longitudinal section of the suction tube 51, for example, substantially equal to the longitudinal dimensions of (all) the print heads 32 of the corresponding color bar 31.

For example, the suction slot 510 has inclined side walls that converge towards the inside of the suction tube 51.

Preferably, the suction groove 510 is (defined by a through eyelet) made in a bottom wall 511 of the suction tube 510 that is oriented towards the support plane, in which the bottom wall 511 is substantially flat (and lies on a plane parallel to the support plane of the conveyor 20).

The distance between each suction slot 510 and the (print head row 32 of the) related color bar 31 is preferably limited, eg, substantially equal to (or comparable to) the width of a print head row 32.

The bottom wall 511 (i.e. its underside) is substantially coplanar with the bottom wall (i.e. its underside) of the respective color bar 31 (and juxtaposed thereto, substantially without discontinuity, with respect to the direction of mutual juxtaposition).

In other words, the suction slot 510 is substantially coplanar to the bottom wall (that is, to its underside) of the respective color bar 31, or to the dispensing nozzles of the print heads 32 of the respective color bar. 31.

Each suction tube 51 further comprises an upper closing wall 512, which closes above the lower wall 511.

The upper closing wall 512, for example, has a substantially concave shape, the concavity being directed towards the lower wall 511, for example, in the shape of an inverted "U".

Each suction tube 51 (that is, the assembly between the lower wall 511 and the upper closing wall 512), for example, has a constant cross section along its entire longitudinal development.

The cross section of each suction tube 51 (that is, the assembly between the lower wall 511 and the upper closing wall 512) is open only in correspondence with the suction slot 510.

In addition, each suction tube 51 has a distal end 513 closed by a closing cap 514 and an opposite proximal end 515 open.

The proximal end 515 of each suction tube 51 is connected, as will be better described, fluidically to the suction device 45.

However, it is not excluded (instead of the closing plug 514, too) that the distal end 513 of each suction tube 51 can be fluidically connected to the suction device 45.

Thanks to this, it is possible to achieve a uniform suction throughout the longitudinal development of the suction slot.

Preferably (all) the suction tubes 51 of the first suction device 50 are connected to each other in parallel.

For this, the first suction device 50 advantageously comprises a suction manifold 52 provided with at least one coupling mouth 520 (for example, a plurality of suction mouths 521 equally distributed along the longitudinal axis of the suction manifold) and a plurality of suction mouths 521 (in a number equal to the number of suction tubes 51).

The suction manifold 52 comprises a body elongated along a longitudinal axis inclined, preferably orthogonal, to the longitudinal axis of the suction tubes 51 (for example, also arranged horizontally).

In the example, the coupling mouths 520 (in a smaller number than the number of suction mouths 521) are located on a lower wall of the (elongated body that defines the) suction manifold 52, for example, equidistant from each other along the along the longitudinal axis of the intake manifold itself.

It is not excluded that a (single) coupling mouth 520 may be provided in correspondence with or in the vicinity of an axial end of the (elongated body that defines the) suction manifold 52.

Each coupling port 520 is fluidically connected to the suction device 45 (in parallel), as will be better described below.

The suction mouths 521 are aligned along the longitudinal axis, for example, equidistant from one another, and are preferably made on a side wall of the (elongated body that defines the) suction manifold 52.

Each suction port 521 of the suction manifold 52 is fluidically (tightly) connected to a respective proximal end 515 of a suction tube 51, for example, by the interposition of a gasket 516.

According to one aspect of the invention, the first suction device 50 comprises a plurality of capacity control devices 53, each of which is connected to a respective suction tube 51, in order to regulate the suction power of the respective suction tube 51 (with the same suction power of the suction device 45).

Preferably, each capacity control device 53 comprises a proportional valve, for example, with controlled actuation (that is, a proportional solenoid valve), which is preferably arranged near and/or in correspondence with the proximal end 515 of the respective suction tube 51 (and/or from the respective suction mouth 521 of the suction manifold 52).

Nor is it excluded that each suction tube 51 comprises a plurality (for example, in a number of two) of partialization devices 53, for example, one arranged close to and/or in correspondence with the proximal end 515 of the respective suction tube 51 and the other close to and/or in correspondence with the distal end 513 (when it is not provided with a closure plug 514) of the respective suction tube 51.

In this case, each of the partitioning devices 53 is configured to define a passageway with a variable section (continuously and/or adjustable), between a maximum value (in which the passageway has a substantially equal section to the open section of the proximal end 515 of the respective suction tube 51 and/or of the respective suction mouth 521 of the suction manifold 52) and a minimum value (in which the passageway has a smaller section than the open section of the proximal end 515 of the respective suction tube 51 and/or of the respective suction mouth 521 of the suction manifold 52) at most zero or in any case not zero.

Each partitioning device 53 is configured in such a way that its passage light can adopt any configuration between the maximum value, the minimum value and any intermediate position between the maximum value and the minimum value.

In other words, the capacity control device 53 comprises an actuator configured to actuate a shutter/capacity control device, so that the flow section can be varied as previously described.

According to one aspect of the invention, at least one suction tube 51 (or preferably a plurality of suction tubes 51, even more preferably each suction tube 51) comprises means for varying the suction section, wherein said means of variation are configured to vary the suction section of the suction tube 51 along its longitudinal axis, that is, of the suction slot 510.

In particular, the variation means are configured to regulate the flow rate of sucked air and/or the velocity of the sucked air flow through the suction slot 510 in the direction of its length and/or to compensate for the loss load and/or the flow rate of air drawn in and/or the velocity of the air flow drawn in close to the distal end 513 of the suction tube 51 (especially when the latter is long).

Preferably, the suction means comprise a partitioning wall 54 fixed internally to the respective suction tube 51.

It is not excluded, however, that the partitioning wall is defined integrally with the upper closure wall 512 of the suction tube 51.

For example, the partition wall 54 is elongated along a longitudinal axis parallel to the longitudinal axis of the related suction tube 51 and, advantageously, has a length at least equal to or greater than the length of the suction slot 510.

The partitioning wall 54 is arranged above and/or to the side of the suction slot 510, for example, at a non-zero distance from it.

In practice, the partitioning wall 54 is configured to define, with the lower wall 511, a chamber for the passage of air that flows the air sucked from the suction slot 510 towards the proximal end 515 of the suction tube 51 ( that is, towards the intake manifold 52).

For example, the partitioning wall is defined by a (metallic) sheet, preferably with an inverted "V" or "L" shaped cross section.

For example, the partitioning wall 54 has the possibility of being fixed or stopped inside the suction tube in an adjustable and/or adjustable manner.

Preferably, adjustment means are provided (interposed between the suction tube 51, that is, at least one between the lower wall 511 and the upper closing wall 512, and the partitioning wall 54) that are configured to vary (and set in a certain desired position) the inclination of the partitioning wall 54 with respect to suction slot 510.

In particular, the adjustment means comprise threaded elements that, operated from outside the suction tube 51 (for example, by means of operating wheels), allow the positioning of the partitioning wall 54 with respect to the suction tube 51, i.e. that is, with respect to the lower wall 511 comprising the suction slot 510.

For example, the adjustment means are configured to vary the orientation of the partitioning wall 54 with respect to the (horizontal) plane in which the suction slot 510 is located.

In greater detail, the adjustment means are configured to vary the orientation (of the longitudinal axis) of the partitioning wall 54 between a non-inclined position, in which both axial ends of the partitioning wall 54 are substantially equidistant from the layout plane of the suction slot 510 (that is, the longitudinal axis of the partitioning wall 54 is parallel to the longitudinal axis of the suction slot 510), and at least one inclined position, in which the axial end of the partitioning wall 54 proximally to the distal end 513 of the suction tube 51 is closer to the suction slot 510 with respect to the axial end of the partitioning wall 54 proximally to the proximal end 515 of the suction tube 51.

In practice, in the inclined position the longitudinal axis of the partitioning wall 54 is inclined with respect to the longitudinal axis of the suction slot 510 (by an acute angle), so that the mutual distance decreases from the proximal end 515 towards the distal end 513 of the suction tube 51.

In other words, the regulation means are configured in such a way that when the partitioning wall 54 is arranged in the non-inclined position, the section through which the air drawn in is constant along the longitudinal axis of the suction slot 510, but when the partitioning wall 54 is arranged in any inclined position, the passage section for sucked air decreases along the longitudinal axis of the suction slot 510 from the proximal end 515 to the distal end 513 of the suction tube 51.

In particular, the adjustment means can be configured to regulate the inclination of the partitioning wall 54 so that it remains substantially constant, for throughout the length of the suction slot 51, a suction power and/or a suction flow velocity (compensating for the loss of pressure/ suction power/ air flow velocity that would occur at the end of the suction slot). suction tube 510 proximally to the distal end 513 of the suction tube 51).

The adjustment means can be configured in such a way that the inclination of the partitioning wall 54 is a function of the length of the suction slot 510.

The suction system 40 further comprises a second suction device 60 configured to suck the ink droplets during an inactivity time of the printer 10 (ie when the printing module 30 is in the rest position).

The second suction device 60 comprises a suction carriage 61, which has, for example, an elongated shape along its own longitudinal axis.

Preferably, the suction carriage 61 is arranged with its longitudinal axis orthogonal to the longitudinal axis of the suction tubes 51 of the first suction device 50.

In addition, the suction carriage 61 is arranged below at least one color bar 31, ie below the bottom wall of the color bar 31.

Preferably, the suction carriage 61 is slidable along a (horizontal) sliding direction parallel to the longitudinal axis of the suction tubes 51 of the first suction device.

For example, the suction carriage 61 is slidably supported in the printing module 30, for example, by means of longitudinal guides that support its opposite axial ends.

Preferably, the suction carriage 61 is actuated in a sliding manner by handling means that comprise, for example, an electric motor and elements for transferring movement from the electric motor to the suction carriage 61.

In the example, the suction carriage 61 has a length such that it is arranged below all the color bars 31 of the printing module 30 (ie, it has a length equal to or greater than the width of the printing module 30).

However, it is not excluded that the suction carriage 61 has such a length that it is arranged below a single colored bar 31 (that is, that the second suction device 60 has such a length that it comprises a plurality of suction carriages). aspiration 61, one for each color bar 31, for example, independent of each other).

Preferably, the suction carriage 61 is arranged below each color bar 31 and each suction tube 51, or each suction slot 510.

The suction carriage 61 is mobile by sliding along a sliding direction parallel to the longitudinal axis of the suction tubes 51, preferably alternating between a retracted position (end of stroke and/or rest) and an advanced position (end of career).

At least in the retracted position (end of stroke and/or rest) and/or in the advanced position (end of stroke), the suction carriage 61 is misaligned in plan with respect to each print head 32 of the color bars 31, in practice not obstructing the printing zone.

The retracted position is proximal to the proximal end of the suction tubes 51 and the advanced position is proximal to (and/or in correspondence with) the distal end of the suction tubes 51.

The suction carriage 61 is configured to suck the ink droplets as it moves (forward and/or backward) along the sliding direction between its retracted position and its advanced position.

The suction carriage 61 is in the form of a suction tube (for example, quadrangular in section) which has an upper wall facing the lower wall of the colored bar(s) 31, that is, towards the suction heads. impression 32.

Preferably, the suction carriage 61 comprises, for example, on its upper wall, at least one suction shoe 610 defining a suction slot 611 elongated along the longitudinal axis of the suction carriage 61.

The suction slot 611 faces upwards and leans against the lower wall of a respective color bar 31.

In the illustrated example, the suction carriage 61 comprises a plurality of shoes 610 (each provided with a respective suction slot 611), one for each color bar 31, which are aligned (and separated from each other) along the Longitudinal axis of the suction carriage 61.

However, it is not excluded that (in case a suction carriage 61 is provided for each individual color bar 31) the suction carriage 61 has a single suction shoe 610 (and a single respective suction slot). .

Each suction shoe 610, for example, is height adjustable with respect to the suction carriage 61.

In addition, elastic elements can be provided between each suction shoe 610 and the suction carriage 61.

These elastic elements allow the upper wall of the suction shoe 610 (and therefore its suction grooves 611) to adhere to the lower wall of the respective color bar 31 and to the lower wall 511 of the corresponding suction tube 51 .

In addition, each suction shoe 610 is made of or coated (on top) with a plastic material, for example, with low friction (such as polyoxymethylene, POM).

Each suction shoe 610 surrounds the entire perimeter of the suction slot 611.

The suction slot 611, for example, has a length at least equal to the width of all rows of print heads 32 of the respective color bar 31.

Preferably, the suction slot 611, for example, has a length greater than the width of all rows of print heads 32 of the respective color bar 31, for example at least equal to the sum of the width of all rows. rows of print heads 32 of the respective color bar 31 and the distance between the suction slot 510 of the suction tube 51 proximal to (or immediately after) the respective color bar 31.

In practice, the suction slot 611 is configured so that an axial part thereof is (vertically) aligned in plan, during sliding of the suction carriage 61 along the sliding direction, with all the suction heads. impression 32 (of each row) of each color bar and with the suction slot 510 of the respective suction tube proximal to (or located immediately after) the respective color bar 31.

In other words, the suction slot 611, during the sliding of the suction carriage 61 along the sliding direction, is configured to suck the ink drops that are deposited below the respective color bar 31 (i.e. , in sequence each print head 32 of the same) and in correspondence with the suction slot 510 of the suction tube 51 proximal with respect to (or positioned immediately after) the color bar 31 itself.

The suction shoe 610, i.e. its upper surface, is configured to rub (with reduced friction) the lower wall of the respective color bar 31 and the lower wall 511 of the respective suction tube 51 during sliding of the suction carriage. 61 along the sliding direction (in order to optimize the suction of the ink drops by means of the suction slit 611).

The suction carriage 61 comprises a distal axial end (for example, arranged downstream in the direction of advancement of the plates S along the direction of advancement A), which is preferably closed by a plug, and a proximal axial end opposite, in correspondence with or close to which an inlet 612 is arranged.

The inlet 612 of each suction tube 51 is fluidically connected, as will be better described, to a suction device (configured to draw a flow of air from each suction slot 611), preferably the same suction device. 45 described above.

Advantageously, then, the suction carriage 61 comprises at least one cleaning appendage 613, which preferably rises above the suction carriage 61, that is, above its upper wall.

The cleaning tab 613 is made, for example, of a material that yields (flexing and/or compression), for example, elastically, such as rubber.

The cleaning tab 613 is configured to enter (vertically) the suction slot 510 of a suction tube 51, for example, by rubbing/scraping the inner walls thereof while sliding the suction carriage 61 along the direction Sliding.

In practice, the cleaning tab 613, during sliding of the suction carriage 61 along the sliding direction, slides axially along the suction slot 510 of a suction tube 51 (grinding its inner walls by rubbing).

The cleaning appendage 613 is arranged close to an axial section of the suction slot 611 (of the suction shoe 610), for example, on a front face thereof (in the direction of sliding of the suction carriage 61 from the retracted position to its advanced position).

Preferably, in the illustrated example, the suction carriage 61 presents a plurality of cleaning tabs 613, for example one for each suction tube 51, each of which is configured to enter a respective suction slot 511 during cleaning. sliding of the suction carriage 61 along the direction of sliding.

It is not excluded that, in case a suction carriage 61 is provided for each color bar 31, each suction carriage 61 may present a single cleaning appendage 613 configured to enter the respective single suction slot 511 under the carriage suction 61.

As mentioned, in the shown embodiment, the same suction device 45 is fluidically connected to the first suction device 50 and to the second suction device 60.

For example, the suction system 40 comprises a selection valve 450 configured to selectively switch the suction system 40 between a first suction mode by means of the first suction device 50 (during printing by the printer 10) and a second suction mode by means of the second suction device 60 (during a phase of inactivity of the machine).

Preferably, selection valve 450 comprises:

- a first inlet fluidically connected, for example by means of a conduit, to the coupling mouth 520 (ie to each of them) of the suction manifold 52;

- a second inlet fluidically connected, for example by means of an additional conduit, to the inlet mouth 612 of the suction carriage 61; and

- an outlet fluidically connected, for example by another conduit, to a suction mouth of the suction device 45.

Selector valve 450 is, for example, an electrically actuated valve, eg a knife gate valve, preferably provided with an actuator configured to switch selector valve (knife) 450 between a first operating configuration, in which which (the sash) occludes the second inlet (allowing airflow from the first inlet to the outlet), and a second operating configuration, in which (the sash) occludes the first inlet (letting air flow from the second entrance to exit).

For example, the selection valve 450 is apt to be arranged in its first operating position during printing (ie, when the printing module 30 is in its working position and the suction carriage 60 is in its retracted position). and in its second operating position during a stop phase of the machine (ie, when the printing module 30 is in its rest position and the suction carriage 60 alternates between the retracted position and the advanced position).

According to another aspect, the printer 10 comprises a cleaning system 70 configured to clean the print heads 32 (for example, by assisting the aforementioned aspiration system).

For example, the cleaning system 70 is configured to intervene, preferably, when the printer 10, or its printing module 30, is used with high-dry inks, for example, water-based, which tend to dry quickly in stationary conditions. .

The cleaning system 70 is configured to dispense a cleaning fluid, such as, for example, a liquid, which wets the print heads 32 (i.e., the nozzles). dispensers thereof and the parts adjacent to them), in order to moisten any ink encrustation that may have formed on them.

In detail, the cleaning system 70 is configured to intervene during a time of inactivity of the printer 10, that is to say, when the printing module 30 is in the rest position (before and/or simultaneously with the intervention of the second device of aspiration 60).

The cleaning system 70 comprises at least one car wash 71 which, for example, has an elongated shape along its own longitudinal axis.

Preferably, the cleaning carriage 71 is arranged with its longitudinal axis (horizontal y) parallel to the longitudinal axis of each color bar 31 (ie, of the suction tubes 51 of the first suction device 50).

In addition, the cleaning cart 71 is arranged below at least one color bar 31 (or each of them), or below (at a lower height) the lower wall of the color bar 31 (preferably at lower height than the suction carriage 61), for example, when the printing module 30 is arranged in its rest position.

Furthermore, the cleaning trolley 71 is arranged above the conveyor 20 (ie the transport unit itself).

Preferably, the cleaning carriage 71 is movable by sliding along a translational (horizontal) direction, which for example is parallel to the direction of advance A, that is to say orthogonal to the longitudinal axis of each color bar 31.

For example, cleaning cart 71 is supported smoothly on conveyor 20, preferably on its support frame 21, for example, by longitudinal guides supporting its opposite axial ends.

Preferably, the cleaning trolley 71 is driven by sliding by drive means, which comprise, for example, an electric motor and movement transfer elements from the electric motor to the cleaning trolley 71.

The cleaning cart 71 in the example has a length substantially equal to the length of each color bar 31 (and/or of the set of rows of print heads 32 of a color bar 31).

The cleaning carriage 71 is mobile by sliding along said direction of translation, preferably alternating between a retracted position (end of stroke and/or rest) and an advanced position (end of stroke).

During sliding, the cleaning carriage 71 performs a sliding stroke in which the cleaning carriage 71 passes under a plurality of color bars 31.

The slide stroke is equal to the length (along the direction of advance) of the printing module 30 or integer submultiples of that length, for example (as in the illustrated case) equal to half of said length.

At least in the retracted position (end of stroke and/or rest) and/or in the advanced position (end of stroke), the cleaning carriage 71 is misaligned in plan with respect to each color bar 31, not obstructing the practical the printing zone, for example, before or after the printing module 30 in the direction of advance of the plates S along the direction of advance A.

In the example, the printer 10 comprises two (opposite) cleaning carriages 71, which move towards and away from each other along the aforementioned translational direction.

In the illustrated case, the cleaning carriage 71 proximal to the upstream end of the conveyor 20 (in the direction of advancement of the plates S along the direction of advancement A) is movable between a retracted position (end of travel and/or rest), in which the cleaning carriage 71 is misaligned in plan with respect to each color bar 31 prior to the printing module 30, and an advanced position (end of run), in which the carriage The cleaning plate 71 is aligned in plan with an intermediate part of the printing module 30, for example it is arranged substantially close to a median plane of the printing module 30 orthogonal to the direction of advance A.

In turn, the cleaning carriage 71 proximal to the downstream end of the conveyor 20 is mobile between a retracted position (end of travel and/or rest), in which the cleaning carriage 71 is misaligned in plan with respect to each bar. color 31 after the printing module 30, and an advanced position (end of stroke), in which the cleaning carriage 71 is aligned in plan with an intermediate part of the printing module 30, for example it is arranged substantially close to a median plane of the printing module. impression 30 orthogonal to the direction of advance A.

The cleaning carriage 71 is configured to dispense a cleaning (and/or descaling) fluid towards the printheads 32 of each color bar 31 to which it is subtended on its slide stroke between the retracted position and the advanced position.

The cleaning fluid, for example, has a composition that is a function of the ink used in the color bars 31 of the printing module 30.

Cleaning fluid, for example, is a liquid configured to descale/thin/dissolve scale from dried ink.

The cleaning trolley 71 has the shape of a dispenser tube (for example, circular in section) with an upper part facing the lower wall of the printing module 30, that is, towards the color bar(s) 31 and , therefore, towards the print heads 32.

Preferably, the cleaning cart 71 comprises, for example, in correspondence with its upper part, at least one cleaning fluid dispensing unit configured to dispense a jet of cleaning fluid, preferably upwards, that is, towards the cleaning heads. printing 32 of a color bar 31 which is substantially above the cleaning carriage 71, preferably aligned (vertically) in plan with the same.

The dispensing unit comprises or consists of one or, preferably, a plurality of nozzles 710, preferably mist nozzles, each of which is configured to dispense a stream of preferably misted cleaning fluid.

In the illustrated example, the dispensing unit comprises a plurality of nozzles 710, which are aligned (and spaced from one another, preferably equidistant) along the longitudinal axis of the cleaning cart 71, for example, in a single row (or in a plurality of rows, for example, staggered).

Each nozzle 710, for example, is rigidly fixed to the cleaning cart 71, for example, removably, and/or can be fixed in a height-adjustable manner and/or inclination with respect to the cleaning trolley 71.

For example, a respective filter is interposed between each nozzle 710 and the cleaning cart 71.

The row of nozzles 710 extends longitudinally through a central section of the longitudinal development of the cleaning carriage 71, presenting, for example, a length equal to the (maximum) length of all the rows of print heads 32 of one (or each ) color bar 31.

In practice, the row of nozzles 710 is configured in such a way that the jet of cleaning fluid (mist) dispensed by the nozzles 710 of the row (presenting a sheet shape of cleaning fluid mist) is directed toward each row. of print heads 32 of the color bar 31 which, during the sliding of the cleaning carriage 71, is substantially above the cleaning carriage 71, preferably aligned (vertically) in plan with the same).

In other words, the row of nozzles 710, during the sliding of the cleaning carriage 71 along the direction of translation, is configured to dispense a sheet of nebulized cleaning fluid (defined by the set of cleaning fluid jets dispensed by each nozzle 710 in the row) that is configured to wet the dispense nozzles and print heads 32 (and/or adjacent areas thereto) of the color bar 31 (which is located substantially above the print carriage). cleaning 71, preferably aligned (vertically) in plan with it).

Each cleaning cart 71 and/or dispensing unit, for example, is configured/programmed to dispense a jet of cleaning fluid mist (i.e., a sheet of cleaning fluid mist) intermittently during the sliding of the cleaning cart. 71, for example, so that a stream of mist cleaning fluid (i.e., a sheet of mist cleaning fluid) is dispensed only in correspondence with the rows of print heads 32 of each color bar 31 and/or in correspondence with the suction slot 510 of each suction tube 51 during the sliding of the cleaning carriage 71.

In practice, the dispensing unit may be programmed to dispense an intermittent stream of cleaning fluid with emission of the stream of cleaning fluid only when the washing carriage 71 is arranged substantially below, preferably (vertically) aligned in plan, with a respective row of print heads 32 of a color bar 31 and/or a suction slot 510 of a suction tube 51 during sliding along the direction of translation.

To this end, the cleaning cart 71 may be provided with an on/off valve, eg electrically actuated, which is configured to selectively open and close (intermittently along the length of the cleaning cart 71) fluid dispensing. cleaning by means of the dispensing unit.

However, it is not excluded that each cleaning cart 71 may instead be configured to dispense a jet of mist cleaning fluid (i.e., a sheet of mist cleaning fluid) continuously during the sliding of the cleaning cart. 71 (and interrupt dispensing only in correspondence with at least one of the retracted position and the advanced position or both).

Each cleaning cart 71 comprises a distal axial end (for example, arranged proximally with respect to the distal ends 513 of the suction tubes 51), which is preferably closed by a cap, and an opposite proximal axial end, in correspondence with which or in the vicinity of which an outlet 711 is arranged.

The cleaning system 70 further comprises a cleaning fluid reservoir 72, preferably fixed (ie, placed on the support frame 21 or resting on the floor at a position remote from the printer 10).

The dispensing unit (ie, each of the nozzles 710) and/or the cleaning cart 71 are fluidically connected to the reservoir 72.

Preferably, outlet 711 of each cleaning cart 71 is fluidically connected to reservoir 72, for example, by a cleaning fluid supply line.

Furthermore, the cleaning system 71 comprises a cleaning fluid supply pump, which is interposed between the cleaning carriage 71 and the reservoir 72, for example, it is placed in the supply pipe.

The supply pump is, for example, an electrically driven pump.

For example, a filter is interposed between the tank 72 and (the suction branch of) the supply pump.

Cleaning system 70 comprises at least one collection tray 73, which is preferably configured to collect cleaning fluid and/or ink dissolved by cleaning fluid (i.e., leachate) after/during dispensing of cleaning fluid. cleaning by the dispensing unit.

The collection tray 73, for example, has a bottom wall (essentially quadrangular) and side walls (eg 4 in number) rising (vertically) from the lateral perimeter of the bottom wall.

The bottom wall and/or one or more of the side walls have a discharge outlet connected to a leachate discharge conduit, which conveys the leachate to a leachate collection tank.

The bottom wall is essentially horizontal and/or has a slight slope, so that it transports the collected leachate towards the discharge mouth.

Furthermore, the collection tray 73 is arranged below at least one color bar 31 (or a plurality thereof), or below (at a lower height) the lower wall of the color bar 31 (preferably at a lower height with respect to the suction carriage 61), for example, when the printing module 30 is arranged in its rest position.

Furthermore, the collection tray 73 is arranged above the conveyor 20 (ie the transport unit itself).

Preferably, the collection tray 73 is movable by sliding along a translational (horizontal) direction, which for example is parallel to the direction of advance A, that is, orthogonal to the longitudinal axis of each color bar 31.

For example, the collection tray 73 is slidably supported on the conveyor 20, preferably on its support frame 21, for example, by means of longitudinal guides that support the opposite axial ends (preferably the same longitudinal guides that support the trolley). cleaning 71).

Preferably, the collection tray 73 is driven by sliding by means of drive means comprising, for example, an electric motor and elements for transferring movement from the electric motor to the collection tray 73; Preferably, the drive means of the collection tray 73 coincide with the drive means of the cleaning trolley 71.

The collection tray 73 in the example has a width (along the direction orthogonal to the direction of advance A) substantially equal to the length of each color bar 31 (and/or of the set of rows of print heads 32 of a color bar 31).

Advantageously, the collection tray 73 has a length (along the direction parallel to the direction of advance A) substantially equal to the width of a plurality of color bars 31 (and/or a plurality of modules defined by the set of color bars 31 and the respective suction tube 51 r).

The collection tray 73 is movable by sliding along said direction of translation, preferably alternating between a retracted rest position (limit stroke) and an advanced working position (limit stroke).

During sliding, the collecting tray 73 performs a sliding stroke in which the sliding tray 73 passes under a plurality of color bars 31.

The sliding stroke is equal to the length (along the direction of advance A) of the printing module 30 or integer submultiples of such a length, for example (as in the illustrated case) equal to half of such a length.

At least in the retracted rest position (end of stroke), the collection tray 73 is misaligned in plan with respect to each color bar 31, not obstructing the printing area in practice, for example, anteriorly or posteriorly. to the printing module 30 in the direction of advance of the plates S along the direction of advance A.

In the example, the printer 10 comprises two (opposite) collection trays 73, which are movable toward and away from each other along the aforementioned translational direction.

In such a case, each collection tray 73 has a length (along the direction parallel to the direction of advance A) substantially equal to half the total length of the printing module 30, or equal to half the sum of the widths of the color bars 31 (and/or of the modules defined by the set of color bars 31 and the respective suction tube 51) that make up the printing module 30.

The sliding stroke of each collection tray 73 is, for example, equal to (or slightly greater than) the length of the respective collection tray 73.

In the illustrated case, the collection tray 73 proximal to the upstream end of the conveyor 20 (in the feeding direction of the plates S along the direction of advance A) is movable between a retracted rest position (end of travel ), in which the collection tray 73 is misaligned in plan with respect to each color bar 31 prior to the printing module 30, and an advanced working position (end of run), in which the collection tray 73 is aligned in plan with at least a part of the printing module 30, for example it is aligned in plan with a front half of the printing module 30 (comprising a plurality of color bars 31 and/or the respective suction tubes 51 ).

In turn, the collection tray 73 proximal to the downstream end of the conveyor 20 is movable between a retracted rest position (end of stroke), in which the collection tray 73 is misaligned in plan with respect to each color bar. 31 behind the printing module 30, and an advanced working position (end of stroke), in which the collection tray 73 is aligned in plan with at least a part of the printing module 30, for example it is aligned in plant with a rear half of the printing module 30 (comprising a plurality of color bars 31 and/or the respective suction tubes 51).

Each collection tray 73 is configured to collect the leachate (which falls off by gravity) from each color bar 31 (and/or suction tube 51) to which it is subtended in its sliding stroke between its retracted rest position and its forward working position and/or in its forward working position.

Preferably, each cleaning trolley 71 is rigidly fixed to its respective collection tray 73 (that is, it is integral with it), for example, in correspondence with or in the vicinity of a front end thereof in the forward direction of the collecting tray 73 from the retracted rest position towards the advanced working position.

In the example, the cleaning trolley 71 is rigidly fixed inside the collection tray 73, for example, it is fixed inside a front side wall thereof (advance direction of the collection tray 73 from the position of rest retracted towards the forward working position).

However, it is not excluded that the cleaning carriage 71 may be rigidly attached to the outside of the collection tray 73, for example, attached to the outside of a front side wall thereof (advance direction of the collection tray 73 from the retracted rest position to the forward working position).

Furthermore, it is not excluded that there may be more than one cleaning trolley 71 (parallel to each other) coupled to the collection tray 73, for example, one for each color bar subtended to the collection tray 73 when the latter is in the position advanced work.

Furthermore, it is not excluded that each collection tray 73 can be detached from the cleaning cart 71.

For example, each collection tray 73 can be supported by sliding guides and can be movable/extractable/removable, preferably along the extraction direction (of the color bars 31).

For example, it is also possible that the printer 10 is provided with a collection tray 70 for each color bar 31 (fit to be placed below it).

The printer 10 further comprises an electronic control unit 80 (and/or the suction system 40 and/or the cleaning system 70) comprises an electronic control unit 80 (illustrated schematically in figure 1), which manages the operation, in automatic mode, of the printer 10 and/or the suction system 40 and/or the cleaning system 70, as described below.

The electronic control unit 80 comprises, for example, a programmable or programmed processor to execute the operating phases and a memory unit.

The printer 10 further comprises an interface module 85 comprising, for example, a user interface, provided with a monitor and/or an indicator (visual and/or audible or tactile), preferably provided with an input module (for example , selector and/or keyboard or touch-screen device).

The interface module 85 may be operatively connected to the electronic control unit 80.

Advantageously, the electronic control unit 80 is operatively connected to the printing module 30, preferably to each color bar 31 thereof, for example, to receive (respective signals indicative of) information relating to one or more printing parameters and/or or to send them (some respective signals indicative of) printing commands.

In addition, the electronic control unit 80 is operatively connected to the motorization of the printing module 30 responsible for moving it between the work and rest positions, to control its operation.

Furthermore, the electronic control unit 80 is operatively connected to the suction system 40 to control its operation, as will be shown below.

Preferably, the electronic control unit 80 is operatively connected to the suction device 45 (that is, to the suction power variation means thereof) and/or to the first suction device 51 (that is, to each suction device). partitioning 53), in order to control its operation.

Furthermore, the electronic control unit 80 can be operatively connected to the second suction device 60 (ie to the means for movement of the suction carriage 61), in order to control its operation.

Electronic control unit 80 is also operatively connected to selector valve 450 to control its operation.

Finally, the electronic control unit 80 is operatively connected to the cleaning system 70 (for example, to the drive means of the cleaning cart 71 and/or of the collection tray 73 and, preferably, to the dispensing unit, that is, at least one between the cleaning fluid supply pump and the opening/closing valve of the cleaning cart 71) to control its operation.

The electronic control unit 80, for example, is configured/programmed to perform a suction control method for the suction system 40, with detail of the first suction device 50.

The suction control method is described below with reference to the flowchart of Figure 9.

The method consists in determining (block S1) a value of a parameter indicative of the volume of ink that is ejected from each color bar to perform a decoration on at least one plate S (that is, on each plate S) to be decorated. .

For this, for example, the method consists in receiving (block S1.1) an image of the decoration to be printed on each plate S.

The image is made available to the electronic control unit 80 via an input module, for example defined in the interface module 85.

Next, the method provides for decomposing (block S1.2) the image into a plurality of monochrome subimages, wherein each monochrome subimage is combined with a respective color bar 31 for printing on the plate S.

In practice, the electronic control unit 80 is such that it decomposes the image into said sub-images assigned to a respective color bar 31, and then commands each color bar 31 to execute a respective part of the decoration on the plate. S playing the respective sub picture.

Therefore, the method is to calculate (block S1.3) the value of the parameter indicative of the volume of ink required by each color bar 31 to make the respective part of the decoration on the plate S based on each respective monochrome sub-image.

In particular, the electronic control unit 80 detects, for each subimage, a value corresponding to the number and/or to the density and/or to the size of the pixels and/or of the dots. composing the sub-image and calculates (by adding) the value of the parameter indicative of the ink volume based on the detected value.

For example, the detected value is first converted to a value expressed in weight or volume by multiplying the detected value by a correction parameter, wherein the correction parameter is stored in the memory unit of the electronic control unit 80 and has been defined through precalibration operations.

The correction parameter depends, for example, on the type of ink loaded in the respective color bar 31.

Preferably, the value of the ink volume indicative parameter is expressed in a coverage value, for example, defined on a percentage scale (0 to 100%).

Preferably, then, the method can optionally provide for calculating (block S2) the maximum of the values of the parameter indicative of ink volume (that is, of the coverage values) determined from the different color bars 31 of the printing module 30.

In such a case, the method may provide for determining (block S3) a maximum value of suction power based on the maximum value of the calculated ink volume indicative parameter.

For example, the maximum value of the suction power can be provided as the output of a table or a map (pre-calibrated during the calibration of the printer 10 and stored in the memory unit) that it receives as input (from English, "input") the maximum value of the calculated ink volume parameter.

The method provides for controlling (by means of the electronic control unit 80) the suction device 45 (or the means for varying it) so that it generates a suction flow at said determined maximum suction power value.

However, it is not excluded that the maximum determined suction power value may be constant and/or that the suction device 45 (or the means for varying it) generates a suction flow with a constant suction power.

Preferably, the method comprises determining (block S4) a value of a (desired) suction power for each suction tube 51 (associated with a respective color bar 31) based on the value of the determined/calculated ink volume indicative parameter. .

The (desired) suction power value is preferably less than or at most equal to the determined maximum suction power value.

In detail, the method provides for determining a plurality of (desired) suction power values, one for each suction tube 51 (associated with a respective color bar) and univocally associated with it (and corresponding to/depending on the value of the parameter indicative of ink volume, ie the coverage value, calculated for each respective color bar 31).

For example, each (desired) suction power value can be provided as the output of a table or a map (pre-calibrated in the calibration phase of the printer 10 and stored in the memory unit) which receives as input a respective value of the parameter indicative of the ink volume (ie the coverage value) determined/calculated.

Alternatively, each suction power value (desired) can correspond to the coverage value expressed as a percentage.

Thus, the method provides for controlling (block S4), for example, by means of a command given by the electronic control unit 80, each capacity control device 53 to operate the respective suction tube 51 at the relative value of suction power (desired). certain.

For example, if the determined/calculated coverage value for a color bar 31 is 100%, then the partialization device 53 of the suction tube 51 associated with said color bar 31 is controlled, so that the passing light of the same is at its maximum value (that is, it does not produce a partialization of the air flow in said suction tube 51) and the suction power value (desired) in said suction tube 51 is equal to the maximum power value suction (generated by the suction device 45).

If, on the other hand, the coverage value determined/calculated for a color bar 31 is equal to a percentage between 0% and 100% (excluding the extremes), for example 80%, then the partialization device 53 of the suction tube 51 associated with said color bar 31 is controlled, in such a way that the clearance of the same is fixed at an intermediate value between the maximum value and the minimum value, (that is, it produces a partialization of the air flow in such a suction tube 51), for example corresponding to the percentage of the coverage value with respect to the maximum value (for example, 80% of the maximum value); in such a case, the value of the suction power (desired) in such a suction tube 51 is equal to the percentage of the maximum value of the suction power (generated by the suction device 45).

In the limit, if the coverage value determined/calculated for a color bar 31 is 0%, then the partialization device 53 of the suction tube 51 associated with said color bar 31 is controlled, in such a way that the light of passage of the same is at the minimum value (for example, 5%), that is, it produces an occlusion of the air flow in said suction tube 51 and the value of suction power (desired) in said suction tube 51 is null.

Thus, the aforementioned suction control method is capable of dynamically modulating the suction power for each individual color bar 31 in order to maximize ink mist capture by the respective suction tube 51 and minimize the deflection of the ink drops emitted by the print heads 32 directed to the plate S.

Taking into account the above, the operation of the printer 10 is as follows.

During the phase of printing on the plates, the printing module 30 is arranged in its working position, the conveyor 20 supplies at least one plate S at a time along the direction of advance A below the printing module 30.

In particular, during the advance of the plate S along the direction of advance A, this passes under the color bars 31, which will dispense onto it, by means of the printing heads 32, a respective part ( monochromatic) of decoration.

During this printing phase, the electronic control unit 80 controls the selection valve 450 in its first suction mode, that is, in such a way that the suction air flow passes through the first suction device 50.

With selection valve 450 in its first suction mode, electronic control unit 80 performs the suction control method described above.

Periodically or as needed, the printer 10 and/or electronic control unit 80 are programmed or controlled to perform a cleaning cycle on the print heads 32.

To carry out this cleaning cycle, the electronic control unit 80 first controls, for example, the stopping of the conveyor 20 and the raising of the printing module 30 to its rest position.

Subsequently, the electronic control unit 80 switches the selection valve 450 to its second suction mode, ie in such a way that the suction airflow can pass through the second suction device 60.

Simultaneously (or successively), for example, after a possible phase of purging the dispensing nozzles of the print heads 32, the electronic control unit 80 is configured to carry out a phase of aspiration of the print heads 32 and /o of the suction tubes 51 carried out by means of the second suction device 60.

In this suction phase, the electronic control unit 80 controls the suction carriage 61 so that it performs at least one sliding stroke along the sliding direction (preferably in both directions) between the retracted position and the advanced position, thus sucking the ink drops that may have been deposited in correspondence with/near the print heads 32 of each color bar 31 and/or the suction slot 510 of each suction tube 51.

Each cleaning appendage 613, during the sliding stroke, enters the suction groove 510 of the respective suction tube 51 and loosens possible accumulations of dirt from it, allowing them to be effectively vacuumed by (the respective suction slot 611 of) the suction trolley 61.

Preferably, just before or at the beginning of the cleaning cycle, as soon as the printing module 30 is raised towards its rest position (before it reaches that rest position), the electronic control unit 80 is configured to anticipate the switching of selector valve 450 to its second suction mode.

Simultaneously, the electronic control unit 80 is configured to bring the suction device 45 to the maximum suction power value (performing a predetermined acceleration ramp) just before controlling the sliding of the cleaning carriage 61.

Indirectly, this anticipation of suction by the cleaning carriage 61 while it is still immobile in its retracted position allows any ink residue inside the suction tubes 51 to have time to slide (by gravity) from the interior walls of the suction tube. suction 51 towards the suction slot 510 before the cleaning carriage 61 begins its movement from its retracted position towards its advanced (and return) position; in this way, the suction shoe 610 (as it is shaped, that is to say with its suction slot 611 elongated so that it is also subtended by the suction slot 510 of the respective suction tube 51) will be able to suck up these residues as much as possible of ink previously sucked by the suction tubes 51 and obtain a thorough internal cleaning of the suction tubes 51.

Finally, similarly, as soon as the cleaning carriage completes its return stroke towards the retracted position, just before the printing module 30 descends towards its working position (or during said stroke), the electronic control unit 80 is configured to anticipate the switching of the selection valve 450 to its first suction mode, momentarily leaving the suction device 45 at its maximum suction power value.

In this phase, for example, the electronic control unit 80 brings or has previously brought all the partitioning devices 53 to the configuration in which the passage light assumes the maximum value.

Therefore, thanks to this anticipation phase, the maximum suction power arrives (for a short period of time) to the suction tubes 51, which makes it possible to suck the possible ink residues that may have deposited on the interior walls of the suction tubes 51 (carrying out a thorough cleaning).

At the same time, the electronic control unit 80 commands the suction device 45 to carry out a predetermined deceleration ramp to reach the desired suction pressure value, for example, before the printing module 30 reaches its working position.

Thanks to this, it is possible to minimize and/or eliminate the risk of finding defects (due to drops falling from the suction tubes 51) on the first plate S that is being processed and that enters under the printing module 30 to be printed later. of the cleaning cycle.

Preferably, especially when the printer 10 is intended to be used with high-drying inks (for example, water-based), the aspiration phase (performed by the second aspiration device 60) described above can be preceded by a cleaning step of print heads 32 (and/or suction tubes 51) performed by cleaning system 70.

In particular, the electronic control unit 80 controls each cleaning carriage 71 to perform at least one sliding stroke along the direction of translation (preferably from the retracted rest position to the advanced working position).

Simultaneously, the electronic control unit 80 controls each dispensing unit so that the nozzles 710 dispense a jet of cleaning liquid onto the print heads 32 of each color bar 31 (and/or in correspondence with the suction slot 510 of each suction tube) that they pass through during the sliding stroke.

For example, as mentioned above, electronic control unit 80 may be configured to control the dispensing unit to dispense an intermittent stream of cleaning fluid (coordinated with movement of cleaning cart 71).

In this way, the cleaning fluid dissolves the dried ink droplets possibly present in the area covered by the jet of cleaning fluid.

Each collection tray 73, which moves simultaneously from its retracted rest position to its forward working position, collects the leachates.

In such a case, the purging phase of the dispensing nozzles of the print heads 32 and/or the suction phase of the print heads 32 and/or the suction tubes 51 performed by the second suction device 60 can be performed with each collection tray 73 in the respective advanced working position.

The invention thus conceived is susceptible to numerous modifications and variations, all of which are included within the scope of the inventive concept.

In addition, all the details are replaceable by other technically equivalent elements.

In practice, the materials used, as well as the contingent shapes and dimensions, can be any, according to the requirements, without falling outside the scope of protection of the following claims.

Claims (12)

1. Suction system (40) for a digital inkjet plate printer (10), wherein the digital inkjet plate printer (10) is provided with a plurality of color bars (31), each of them provided with at least one set of inkjet print heads (32), in which the aspiration system (40), characterized in that it comprises: a suction device (45); a plurality of suction tubes (51), including at least one for each color bar (31) of the digital printer (10), wherein the suction tubes (51) are connected to the suction device (45), and are arranged with longitudinal axes parallel to each other and parallel to the longitudinal axes of the color bars (31), wherein the suction tubes (51) of the plurality of suction tubes (51) are connected to each other in parallel ; a plurality of capacity control devices (53), each of which is connected to a respective suction tube (51), in order to regulate the suction power of the respective suction tube (51). System (40) according to claim 1, characterized in that it comprises an electronic control unit (80) operatively connected to each capacity control device (53). System (40) according to the preceding claim, characterized in that the electronic control unit (80) is configured to: determining a value of a parameter indicative of the volume of ink that is dispensed from each color bar (31) for making a decoration on at least one plate; determining a value of a suction power for each suction tube (51) based on the value of the determined indicative parameter; and control each capacity control device (53) so that it works with the determined suction power value. System (40) according to claim 3, characterized in that the electronic control unit (80) is operatively connected to the suction device (45) and is configured to: determining a maximum value of a suction power based on the determined indicative parameter value; and control the suction device (45) to generate the value of the total suction power. System (40) according to claim 3, characterized in that the electronic control unit (80) is configured to: receive an image of the decoration to print it on a plate; decomposing the image into a plurality of monochrome subimages, each monochrome subimage being combined with a respective color bar (31) to print it on the plate; calculating the value of the parameter indicative of the ink volume based on the monochrome subimage. System (40) according to claim 1, characterized in that each suction tube (51) comprises a downwardly oriented longitudinal suction slot (510) which extends over a certain longitudinal section of the suction tube (51). System (40) according to the preceding claim, characterized in that each suction tube (51) comprises means for varying the suction section of each suction tube (51) along the longitudinal axis of the suction slot. (510). System (40) according to the preceding claim, characterized in that the variation means comprise a longitudinal partitioning wall (54) fixed internally to the respective suction tube (51) above the suction slot (510) and means for regulating the inclination of the partitioning wall (54) with respect to the suction slot (510). System (40) according to claim 1, characterized in that it comprises at least one suction carriage (61) arranged with its own longitudinal axis orthogonal to the longitudinal axis of the suction tubes (51) and arranged under at least one bar. color (31) and of the respective suction tube (51), in which the suction carriage (61) is movable by sliding along a sliding direction parallel to the longitudinal axis of the suction tubes (51). System (40) according to claims 6 and 9, characterized in that the suction carriage (61) comprises a suction shoe (610) defining a suction slot (611) elongated along the longitudinal axis of the carriage itself. suction tube (61), in which the suction slot (611) is oriented upwards and the print heads (32) of each color bar (31) and the suction slot (510) of the respective suction tube ( 51) are superimposed in plan on the suction groove (611) of the suction shoe (610) during sliding of the suction carriage (61) along the sliding direction. System (40) according to claims 6 and 9, characterized in that the suction carriage (61) comprises a cleaning appendage (613) configured to enter the suction slot (510) of the suction tube (51) during the sliding of the suction carriage (61) along the sliding direction. 12. Digital inkjet printer (10) for plates, characterized by comprising: a carrier (70) configured to support at least one plate resting on its own lower surface opposite the upper surface to be decorated; a plurality of color bars (31) arranged above the conveyor (20), each color bar provided with at least one set of ink jet print heads (32); and a suction system (40) according to claim 1.