BACKGROUND

[0001] In various technological fields, it may be useful to be generate and precisely control a gas flow, for example to able to displace material from one location to another. In some examples, such material may be a coating, varnishing or priming fluid.

BRIEF DESCRIPTION OF DRAWINGS

[0002] Figures 1A and 1 B are schematic cross sections of an example gas jet device.

[0003] Figure 2 is a schematic cross section of another example gas jet device.

[0004] Figure 3 is a schematic cross section of yet another example gas jet device.

[0005] Figures 4A and 4B are schematic cross sections of an example apparatus.

[0006] Figure 5 is a schematic view of another example apparatus.

[0007] Figure 6 is a schematic view of a further example apparatus.

[0008] Figure 7 is a schematic view of yet another example apparatus.

[0009] Figure 8 is a block diagram of an example method.

[0010] Figure 9 is a block diagram of another example method.

DETAILED DESCRIPTION

[0011] Gas jet devices may be used for different purposes. In a number of cases, gas jetting takes place through a gas jet aperture defined by a gap between a first and a second housing portion, the gas jet device directing a jet of gas selectively and in a controlled manner towards or away from a target area through the gas jet aperture, the control and selectivity being obtained by movement of a deflector arm situated within the aperture. In a first position, the deflector arm is proximate the second housing portion, gas being directed towards the target area. In a second position, the deflector arm is proximate to the first housing portion, the gas following in this case an overlapping surface to be directed away from the target area. An overlapping surface should be understood as a surface integral to or attached or affixed to the second housing portion, the surface facing a tip of the deflector arm, the tip of the deflector arm being at an end of the deflector arm situated within the aperture, the surface overlapping at least partially the tip of the deflector arm. In some examples, the overlapping surface overlaps an area of at least 5%, at least 10%, at least 20%, at least 30%, at least 40% or at least 50% of a cross section of the deflector arm in a plane normal to an axis of the deflector arm. In other words, the overlapping surface comprises an area which is directly below the deflector arm, below being understood in reference to an axis of the deflector arm in the direction of the aperture. In some examples, the target area is an anilox roller, the gas following in this case an overlapping surface to be directed away from the anilox roller. It was found that the overlapping surface should be dimensioned particularly precisely in relationship to a matching surface of the deflector arm, a gas jet channel being formed between the overlapping surface and the matching surface of the deflector arm. Such precision in dimension may depend on the shape of the specific second housing portion and deflector arm used, and may differ from a deflector arm to another, or from a second housing portion to another. In order to compensate for such variability while obtaining an appropriate result, it is proposed in this description to provide an overlapping surface on the second housing portion.

[0012] In some examples the overlapping surface is integral to the second housing portion. In some examples, the overlapping surface is defined by a part separate from and attached to the second housing portion. In some examples, the overlapping surface comprises a polymeric material. The characteristics, in particular the moldability, of a polymeric material indeed permits that the overlapping surface matches the specific second housing portion and specific deflector arm used. Precision of dimensioning permits reducing the ejected gas flow rate and gas consumption while obtaining a satisfactory operation of the gas jet device, in particular by partially blocking and reducing the gas jet in the second position, for example compared to the gas jet in the first position. Such reduced gas flow when in the second position can further contribute to operating the deflector arm using a reduced operating force. In some examples, the precision of dimensioning also permits obtaining an additional physical effect used when directing the gas along the overlapping surface and away from the target area, such affect being called the Coanda effect.

[0013] An example gas jet device 100 is illustrated on figures 1A and 1B. A gas jet device according to this disclosure should be understood as a device for ejection of different types of gas. Example gas include air, steam, nitrogen, nitrous oxide, carbon dioxide, or mixture of different such gases. Other gas may also be considered.

[0014] The example gas jet device 100 comprises a first housing portion 110 and a second housing portion 120 defining a gas jet aperture therebetween. In figures 1A and 1 B, the area of the gas jet aperture is shown magnified in a separate sub figure. In some examples, the first housing portion and the second housing portion are made of metal, such as steel or aluminum for example. Use of metal for the first and second housing portions permits in some cases obtaining a desired stiffness, in particular compared to using plastic materials. In some examples, the first and second housing portion are to contain the gas at a pressure higher than the ambient pressure outside of the gas jet device so that the gas jet may take place.

[0015] Example gas jet device 100 comprises a deflector arm 130 movable within the gas jet aperture between a first position illustrated in figure 1A and a second position illustrated in figure 1B. In some examples, the deflector arm is elongated and is held between the first and second housing portion at a deflector arm end opposite to the gas jet aperture. In some examples, the deflector arm comprises a piezoelectric element used for generating movement of the deflector arm. In some example, the deflector arm comprises multiple layers. In some examples, the deflector arm comprises multiple layers comprising a piezoelectric layer. In some examples, the deflector arm comprises multiple layers comprising two piezo electric layers, whereby the two piezo electric layers may be operated in phase opposition to amplify a movement of the deflector arm, whereby the layers are in a plane substantially parallel to a length direction of the deflector arm. Example piezo electric layer may each have a thickness of more than 0.1 millimeter and of less than 0.3 millimeter. In some examples, the movement of the deflector arm is a flexing movement, one end of the deflector arm being static, for example held between the first and second housing portion at a deflector arm end opposite to the gas jet aperture, while a distal end of the deflector arm may change position in the area of the gas jet aperture by flexing of the deflector arm. To achieve the selective jetting of the gas out of the device the movable deflector arm may be movable between the first and second positions, thereby operating the device according to first and second modes, for example under the control of a controller. For example, the deflector arm may comprise a piezoelectric element and the position of the blade may be changeable by varying the amount of electric current through the arm. In this way the deflector arm may be independently movable. In some examples, the deflector arm is elongated in a direction substantially aligned with the direction of ejected gas when the deflector arm is in the first position. In some of such examples, the deflector arm has a length of at 0.7 centimeter, or at least 1 centimeter, along the direction of ejected gas when the deflector arm is in the first position, and a substantially square cross section along a plane normal to the direction of ejected gas when the deflector arm is in the first position, the cross section being of for example more than 0.5 square millimeter and of for example less than 1.5 square millimeter.

[0016] As illustrated in figure 1A, in the first position the deflector arm is proximate the second housing portion to direct gas between the deflector arm and the first housing portion and toward a target area, the direction of the gas being illustrated by an arrow 140 in figure 1A, the arrow being repeated in the magnified area. In this example, the deflector arm 130 is elongated and the direction of the ejected gas when the deflector arm is in the first position substantially follows the direction along which the deflector arm is elongated. In this example, the first housing portion defines an internal chamber of the gas jet device having a generally funnel shape in order to contribute to directing the gas towards the gas jet aperture. As illustrated in figure 1A, when the deflector arm is in the first position the gas is substantially prevented from passing between the second housing portion and the deflector arm, and is ejected between the deflector arm and the first housing portion. In some examples, when in the first position, the deflector arm is separated from the first housing portion by a gap of more than 20 microns and of less than 100 microns, or of more than 30 microns and of less than 70 microns, or of more than 40 microns and of less than 60 microns, the gas being ejected through such gap.

[0017] As illustrated in figure 1 B, in the second position the deflector arm is proximate the first housing portion to direct gas between the deflector arm and the second housing portion, wherein the gas jet device comprises an overlapping surface 160 such that, when the deflector arm is in the second position, gas is directed away from the target area. The direction of ejection of the gas when the deflector arm is in the second position is illustrated by an arrow 150 which is illustrated in the main figure 1B and in the corresponding magnified area. In this example the overlapping surface contributes to deflecting the gas away from the target, the general direction of ejection of the gas in the first position being in this example at an angle of about 80 degrees to the direction of ejection of the gas when the deflector arm is in the first position. In some examples, an angle between the direction of ejection of gas when the deflector arm is in the first position and the direction of ejection of gas when the deflector arm is in the second position is of more than 30 degrees, more than 45 degrees, more than 60 degrees, more than 75 degrees, or more than 90 degrees. In the example of figure 1B, the deflector arm is elongated, the gas being deflected at an angle away from the direction of elongation of the deflector arm, the gas following the shape of a tip of the deflector arm, the tip being at a flexing, distal end of the deflector arm in this case. In some examples, in order to obtain a satisfactory deflection of the gas and an efficient operation of the gas jet device, a channel followed by ejected gas through the gas jet aperture between the overlapping surface 160 and the deflector arm should be precisely dimensioned, and be adaptable to the specific deflector arm used. In some examples, in order to obtain a precise dimensioning, an overlapping surface 160 is provided. In some examples, such surface is comprised in a separate part, for example a separate part comprising a polymeric material 161 of the gas jet device which defines the overlapping surface 160, the polymeric material being on, or fixedly attached or adhered to, the second housing portion. In some examples, use of a polymeric material permits adapting the shape of the overlapping surface 160 to the shape of the deflector arm in the gas jet aperture area. In this example, the polymeric material takes the shape of a lip placed onto the second housing portion in the gas jet aperture area. In some examples, the polymeric material is an epoxy resin. The polymeric material may comprise one or more synthetic or natural polymers. The polymeric material may have a glass transition temperature permitting adapting the shape of the polymeric material to the specific deflector arm used when the polymeric material is in a liquid or viscous phase, while maintaining the acquired shape during operation of the gas jet device, the polymeric material being in a solid state during operation of the gas jet device. In some examples, part 161 is integral to the second housing portion, and may be for example obtained by machining of the second housing portion. In some examples, when in the second position, the deflector arm is separated from the second housing portion by a gap of more than 0.5 microns and of less than 10 microns, or of more than 1 microns and of less than 5 microns, the gas being ejected through such gap.

[0018] In some examples, the amount of gas ejected by the gas jet device when the deflector arm is in the first position is of more than 4 times the amount of gas ejected by the gas jet device when the deflector arm is in the second position, in some examples of more 5 times the amount of gas ejected by the gas jet device when the deflector arm is in the second position.

[0019] The deflector arm is movable in these examples to direct the gas flow to one of two sides of the deflector arm to therefore direct the airflow in one of two gas channels corresponding either to the first or to the second position. The deflector arm is therefore movable to seal one of two openings on either sides of the deflector arm at the gas jet aperture so that gas is not permitted to enter one of the two gas channels but is permitted to enter the other one of the gas channels. In this way, when one gas channel is opened the other is sealed. In this way, the deflector arm is movable to seal one gas channel and to open another gas channel. The deflector arm is therefore movable to selectively seal and/or open a gas channel of the device.

[0020] Figure 2 illustrates another example gas jet device 200 according to this disclosure. Gas jet device 200 comprises a first housing portion 110, a second housing portion 120, a deflector arm 130 and an overlapping surface 160 as described for example in the context of figures 1A and 1 B, in this case an overlapping surface integral to the second housing portion. Gas jet device 200 further comprises a spacer 270 between the first housing portion and the second housing portion, the spacer having a thickness along a direction of movement of the deflector arm corresponding to the movement between the first and the second position. Such thickness is in this example along a direction perpendicular to a direction of elongation of the deflector arm, and along a direction generally parallel to a direction of movement of the deflector arm between the first and second position. Such spacer may in some examples comprise a shim or a washer. In some examples, the spacer is a metal spacer. In some examples, the spacer permits dimensioning a channel or gap through which the gas may flow, whereby the overlapping surface, for example comprising a polymeric material or being machined, is shaped directly between the second housing portion and the deflector arm prior to introducing the spacer, the polymeric material or the machined overlapping surface thereby taking a shape matching a shape of the deflector arm in the area of the gas jet aperture, the spacer being inserted thereafter in order to define the channel through the gas jet aperture. In such an example, dimensioning of the gas jet aperture is directly dependent on the thickness of the spacer, and may thereby be precisely controlled. Other examples of devices having the overlapping surface may be obtained for example by selective milling of a polymeric material or of a metallic material.

[0021] In some examples, the overlapping surface defines surface matching a surface profile of the deflector arm in the gas jet aperture area. Such surface profile matching can prevent or reduce a risk of the overlapping surface exerting a reaction force against the deflector arm, such reaction force taking an excessive amount when the deflector arm is in the second position. Such reaction force could be caused in some cases by an inherent elasticity of the overlapping surface and by a lack of precision in the dimensioning, the deflector arm pushing against the overlapping surface when in the second position. In some cases, the deflector arm is particularly thin, and sensitive to such reaction forces, which would be applied onto the deflector arm in addition to forces applied by the gas pressure on a first and a second housing portion sides of the gas jet device. In cases where the gas pressure on both housing portion sides of the gas jet device is substantially identical, avoiding a reaction force generated by the overlapping surface permits operating the deflector arm with limited force, such as through a limited piezo force. The piezo force can, in cases of the overlapping surface defining a surface matching a surface profile of the deflector arm in the gas jet aperture area, be substantially used for movement of the deflector arm rather than for “pushing” the deflector arm against the overlapping surface (and being “pushed back” by the reaction force). One also should note that the overlapping surface may be made from a moldable material, thereby permitting obtaining a jet aperture formed by a homogeneous gap between the overlapping surface and the deflector arm.

[0022] Figure 3 illustrates another example gas jet device 300 according to this disclosure. Gas jet device 200 comprises a first housing portion 110, a second housing portion 120, a deflector arm 130 and a overlapping surface comprising for example a polymeric material 161, as described for example in the context of figures 1A and 1B. Gas jet device 300 further comprises a guard element 380, the overlapping surface being located between the guard and the second housing portion. Such a guard element may contribute to defining the shape of the overlapping surface. Such a guard element may protect the overlapping surface from impacts or wear. In some examples, the guard element is made of metal. In some examples, the guard element is fixedly linked to the second housing portion. In some examples, the guard element is manufactured as a part integral to the second housing portion, for example by machining or by extrusion. [0023] Some examples herein relate to forming a pattern of fluid (e.g. liquid) on the surface of a roller. The fluid may comprise a varnish or a coating or a primer, and the roller (to which the fluid is applied) may comprise an anilox roller. The anilox roller may comprise a roller having a plurality of pores (e.g. indentations or cavities) such that when fluid is deposited onto a surface of the anilox roller the fluid is retained in the pores. The anilox roller may then be rotated into contact directly with a substrate (or print media) to transfer the fluid to the substrate (or the anilox roller may be rotated into contact with another, intermediate, roller, for example a rubber roller, which will in turn transfer the fluid to the substrate). The selective discharge of the fluid retained in the pores will cause a fluid image to be formed on the anilox roller by those pores that still retain their fluid, and therefore cause that fluid image to be transferred to the substrate. It may be that certain areas of the substrate are not to be coated with the fluid (e.g. the varnish or coating) in which case, if the anilox roller is coated with a layer of fluid then the fluid may be removed from certain pores so that those corresponding areas of the substrate are not coated with the fluid. Precision of dimensioning according to this disclosure can avoid or reduce undesired streaking. In some examples, the anilox roller is to reach a surface speed of at least 1m/s and of less than 1m/s. In some examples, the density of the pores is of more than 40 pores per centimeter and of less than 480 pores per centimeter. In some examples, the depth of pores is chosen in function of the density, for example a depth of about 10 microns for a density of about 50 pores per centimeter and a depth of about 2 microns for a density of about 500 pores per centimeter, whereby a thicker coating is obtained with deeper pores.

[0024] Some examples herein accomplish the selective removal, or selective discharge, of fluid within a pore of the anilox roller (in order to form a target image onto the substrate) by use of an air knife. According to some examples, an air knife provides a continuous flow of gas (for example, air - the terminology “air knife” encompassing the processing of gas other than air) - for example a “jet flow” - towards the anilox roller. The air knife may extend along the surface of the anilox roller. Put another way, the anilox roller may comprise a length and the length of the gas flow from the air knife may correspond (e.g. substantially correspond) to the length of the roller. In this way, the air knife is able to jet an air flow towards all of the pores of the anilox roller to (selectively, as will now be explained) discharge fluid being retained in the pores. The air knife may be to direct a line of air (or a strip of air) toward the anilox roller as will be explained in more detail later. According to some examples, the air knife comprises a deflector arm (for example a piezoelectric element or electrically controlled element) that is disposed in a gas channel of the air knife. The air knife is to discharge gas through the gas channel and the deflector arm is movable between two positions, each position creating a gas channel defined by one side of the deflector arm and a housing of the air knife (e.g. a housing defining an interior surface of the channel).

[0025] n some examples, the deflector arm may be located in a first position in which gas is directed between the deflector arm and a first housing portion of the air knife and in a second position in which gas is directed between the deflector arm and a second housing portion of the air knife. The deflector arm may be movable between these two positions and therefore movable between positions in which gas is directed through one of two channels. In one position the deflector arm may be positioned such that gas is directed toward the anilox roller (i.e. the target area) to discharge any fluid in a pore of the anilox roller and in the other position the deflector arm may be positioned such that gas is directed away from the anilox roller. In other words, the deflector arm may be movable so as to direct air towards, or away from, the anilox roller to discharge or to not discharge the pores of the anilox roller. The deflector arm may be movable so as to selectively discharge the pores of the anilox roller (by moving the deflector arm between its first and second positions). The air knife may comprise a plurality of adjacent deflector arms along its length such that all of the pores along the length of the anilox roller may be selectively discharged (e.g. discharged or not). Each deflector arm is therefore effectively caused to move to an appropriate position according to whether a pore, or a set of pores, is to be discharged.

[0026] As will be explained below, when directing gas away from the anilox roller, at least part of the housing of the air knife, according to some examples herein, is curved so as to direct gas away from the anilox roller. In this way, the end of the air knife closest to the anilox roller may be located closer to the surface of the anilox roller, while the air knife itself is to direct the air away from the anilox roller.

[0027] The air knife may be a digital air knife sometimes abbreviated to a DAK. In such an air knife, the gas comprises, for example, air, for example pressurized air to produce a jet flow and/or a jet stream of air. In other words, the gas expelled by the device 100 may be discharged from an opening or gas jet aperture of the device at a high velocity. The velocity may be sufficient such that when the gas is directed toward a cavity of the anilox roller filled with fluid (e.g. a liquid) then the liquid in the cavity is expelled. An image can therefore be created upon the surface of an anilox roller by selectively removing liquid out of anilox cavities. The deflector arm, according to the examples presented herein allows the apparatus to selectively apply jet flow in specific areas on the anilox roller to form the fluid image thereon. This image can then be transferred to a substrate (e.g. via the intermediate transfer to another roller, for example a rubber roller). The overlapping surface allows the jet flow to be shifted away from the roller without the use of a separate component. In other words, the air knife itself is able to direct air toward the roller and to deflect the air away from the roller. When the deflector arm is in the second position, the jet flow attaches itself to the overlapping surface and remains attached, following the curvature of the surface. In this second position, the gas jet is diverted sideways in order not to impact the surface of the anilox roller. In addition to this, the structure according to this disclosure can partially block and reduce the gas jet or gas flow ejected in the second position compared to the gas jet ejected in the first position. In this way, the devices bend the jet flow away from a target area on the roller when the jet flow is not to discharge the pores of the roller. The surface is therefore curved so as to pull the jet flow away from the roller. This allows the device to be placed closer to the roller than in examples where a separate component is used to divert the air flow. In turn, this improves the performance of the device. This also makes the design, manufacture, and assembly of the device easier and simpler. Indeed, some examples presented herein accomplish directing air away from the anilox roller, selectively, without the use of an additional component (e.g. a curved blade) which may be expensive or difficult to manufacture (e.g. due to tolerances or to assembly alignment) and, in turn, if an additional component is not used then the air knife is able to be positioned closer to the anilox roller. In this way the length of the “gap” between the air knife and the surface of the anilox roller may be decreased. This decreased distance increases the efficiency of the air knife. In some examples, the gap between the air knife and the surface of the anilox roller is of less than 0.5 millimeter.

[0028] Figures 4A and 4B show an apparatus 400 comprising an air knife and an anilox roller 490 proximate to the air knife, whereby the air knife comprises a housing 410, 420, a gas jet aperture and a deflector arm 430 movable within the gas jet aperture between first (figure 4A) and second (figure 4B) positions wherein, in the first position, air is directed through the gas jet aperture toward a surface of the anilox roller and, in the second position, air is directed through the gas jet aperture along an overlapping surface of the housing and away from the surface of the anilox roller. In this example the apparatus comprises a housing which comprises a first housing portion 410 and a second housing portion 420. The first and second housing portions define a gas jet aperture therebetween. The gas jet aperture is to direct gas (e.g. air) towards or away from roller 490. The roller 490 is an anilox roller and may comprise a number of pores (or indentations or cavities - not shown) for retaining fluid.

[0029] The air knife of apparatus 400 comprises a deflector arm 430. The deflector arm is movable within the gas jet aperture between a first position and a second position. The first position of the deflector arm is shown in figure 4A. The second position of the deflector arm is shown in figure 4B. In the first position the deflector arm 430 is proximate the second housing portion 420 to thereby direct gas between the deflector arm 430 and the first housing portion 410. This is shown by an arrow in figure 4A. In the second position (figure 4B) the deflector arm is proximate the first housing portion 410 to thereby direct gas between the deflector arm 430 and the second housing portion 420. This is shown by an arrow in figure 4B. Referring to figure 4A, when the deflector arm 430 is in the first position, the air knife is to direct gas towards a target area of the roller. The housing comprises an overlapping surface 461 such that when the deflector arm 430 is in its second position, shown in figure 4B, gas is directed away from the target area due to the Coanda effect.

[0030] In the example of figures 4A and 4B, the first housing portion 410 defines, or comprises, a first arm 417. The second housing portion 420 defines, or comprises, a second arm 427. The apparatus therefore comprises first and second opposing arms 417, 427 defining a gas channel therebetween. Each of the first and second arms extends away from, and back towards, the deflector arm 430 so as to define a gas chamber in the air knife, the gas chamber being delimited in respective sub chambers by the first and second housings 410, 420 and the deflector arm 430.

[0031] Figure 5 illustrates another apparatus 500, the apparatus 500 comprising an air knife 501 and an anilox roller 590 proximate to the air knife, whereby the air knife comprises a housing, a gas jet aperture and a plurality of deflector arms movable between respective first and second positions, the plurality of deflector arms 530-1 to 530-N being positioned adjacent to each other along an axis parallel to a fixed rotation axis of the anilox roller, each deflector arm movable within the gas jet aperture between first and second positions wherein, in the first position, air is directed through the gas jet aperture toward a surface of the anilox roller and, in the second position, air is directed through the gas jet aperture along an overlapping surface of the housing and away from the surface of the anilox roller. Apparatus 500 permits operating the air knife selectively along a length of the anilox roller. In some examples, each deflector arm of the plurality may be operated independently from other deflector arms, thereby permitting selectivity along the full length of the deflector arms. In some examples, the deflector arms are grouped by modules of about 60 adjacent deflector arms.

[0032] Figure 6 illustrates another apparatus 600, the apparatus 600 comprising an air knife such as air knife 501 described in the context of Figure 5, an anilox roller 690 and a printer 602. The air knife and anilox roller are in this example located on a printing media path of the printer 602. The air knife and anilox roller may be located on entry of the media path into the printer, for example for pre-treatment of the media. The air knife and anilox roller may be located on exit of the media path from the printer, for example for post-treatment of the printed media. In other examples, an air knife and a roller may be provided both on entry and on exit of a printer media path to accommodate for both pre- and post-treatment of printing media. In some examples, the printer is a printer to print on cardboard, labels or packaging materials, the anilox roller having a length along a rotation axis of at least 29.7 centimeter to accommodate for relatively large format printing media. In other examples, not represented here, an apparatus according to this disclosure may further comprise a printing press or a coating machine.

[0033] Figure 7 illustrates another apparatus 700, the apparatus 700 comprising an air knife 701 such as the air knife described in the context of Figure 5 or the air knife described in figures 4A-B, an anilox roller 790 and a source 703 of pressurized gas to generate a pressure in the air knife. Source 703 may be connected by one or more conducts to an internal chamber of the air knife, source 703 being thereby fluidically connected to the gas jet aperture of the air knife through such internal chamber. In some examples, the source of pressurized gas is to generate a pressure of more than 500 kPa in the air knife during operation of the air knife. In other examples, the pressure generated is of more than 600 kPa or of more than 700kPa. Such pressures may be obtained and maintained within the air knife due to the precise dimensioning of the gas jet aperture obtained by use of the overlapping surface as per this disclosure. An inlet of the source may feed airflow and/or pressure into the air knife. Due to the precision of the dimensioning obtained by use of the overlapping surface, in some examples satisfactory operation may be reached with a quantity of gas ejected through the gas jet aperture of less than 20 liters per minute, or in some cases less than 5 liters per minute, when the deflector arm is in the second position, i.e. diverting the gas away from the target area, and of more than 120 liters per minute when the deflector arm is in the first position, i.e. ejecting the gas directly onto the target area. In some examples, the techniques according to this disclosure permit using relatively less powerful compressors, and reduce ambient noise. [0034] Figure 8 illustrates an example method 800 of manufacturing a gas jet device. Such method may serve to manufacture one of the gas jet devices or apparatuses hereby described. In block 801, method 800 comprises enclosing a deflector arm of the gas jet device between a first housing portion and a second housing portion of the gas jet device. By enclosing, it should be understood that both the first housing portion and the second housing portion are brought into contact at at least one point with the deflector arm.

[0035] In block 802, method 800 comprises applying a polymeric material between the deflector arm and the second housing portion as the deflector arm is enclosed, to produce an overlapping surface. This block permits shaping the polymeric material such that the overlapping surface matches a corresponding surface of the deflector arm. One should note that each deflector arm may have its own specific shape. In some examples, the polymeric material is applied at a temperature above glass transition temperature of the polymeric material during block 802. The application of the polymeric material takes place between the deflector arm and the second housing portion in order to precisely generate the overlapping surface which will serve to direct the gas away from the target area when the deflector arm is in the second position and can contribute to the forming a uniform gap corresponding to the gas jet aperture.

[0036] In block 803, method 800 comprises introducing a spacer between the first housing portion and the second housing portion to define a gas jet aperture between the overlapping surface of the polymeric material and the second housing portion. During block 803, the polymeric material may be in a solid phase. Beyond the gas jet aperture, the introduction of the spacer can generate a channel through which the gas may be ejected.

[0037] Another example method 900 of manufacturing is illustrated in figure 9. The method 900 comprises blocks 801 , 802 and 803 as described in the context of example method 800. Example method 900 further comprises applying the polymeric material between the deflector arm and a surface portion of the first housing portion, such that the polymeric material may serve to precisely dimension a channel followed by the gas through the gas jet aperture when the deflector arm is in the first position.

[0038] In any of example methods 800 or 900, the spacer may be a shim, the shim having for example a thickness between the first and second housing portions of less than 0.5 millimeter, of less than 0.3 millimeter, or of less than 0.1 millimeter. [0039] When applying any of examples methods 800 or 900 to an apparatus comprising a plurality of deflector arms movable between respective first and second positions, the plurality of deflector arms being positioned adjacent to each other along an axis parallel to a fixed rotation axis of the anilox roller, the methods permit to simultaneously adapt the dimensions of each gas jet aperture corresponding to each deflector arm, thereby taking into account the shapes of each deflector arm of the plurality.