Facility for coating the desings on the ribbon material

A major drawback of the known application nozzles is the marked outline of the applied pattern. The reasons for this drawback, in particular if no greater amounts of paint are to be applied, are in particular that spray nozzles suitable for the application of the required amount of paint must be used which cause undesirable disturbances when the application is interrupted.

Each nozzle behaves in such a way that the flow rate does not drop to zero at infinite time, but that the nozzle is completely closed after a certain time. The end of the tearing liquid stream is still narrowing at this time because the liquid residue adheres to the applicator nozzle due to the viscosity. In addition, the liquid output velocity decreases considerably as a result of the nozzle being closed, so that the liquid particles at the end of the liquid jet have no tendency to leave the nozzle. If the applicator nozzle is arranged at a greater distance from the web material, the last liquid particles need considerably longer time to overcome this distance than the particles that have exited the applicator nozzle at full speed. If the applicator nozzle is disposed away from the printed web material, it occurs. as a consequence of the described phenomena to a considerable extension of the spray, i.e. to blur the boundary of the applied paint. The intrinsic viscosity, together with the elasticity of the paint, results in a large amount of paint between the non-applicator nozzle and the web material allowing a significant elongation of the ink jet, which is another cause of the elongation of the spray and the contoured blur of the applied pattern. In this case, it is irrelevant whether the interruption of the ink jet has occurred as a result of the application nozzle being closed or has been forced by a secondary air flow that extends transversely to the direction of the ink jet.

These drawbacks are overcome by a web-based pattern-applying apparatus comprising dispensing nozzles provided with a feed material disposed above a web-conveyor mounted on support rollers, under which a vacuum chamber, the essence of which is based on the invention, The application nozzles are provided with shut-off needles connected mechanically to movable coils or magnetic anchors and are disposed against the support rollers and vacuum chambers at a distance of 0 to 5 mm from the surface of the web material. A distance in the range of 0.5 to 2 mm is particularly preferred.

The support rollers are preferably arranged in the vacuum chambers, which are distributed in the vacuum chambers, which are distributed along the underside of the conveyor.

The conveyor is of a gas permeable material, preferably a sieve, and a portion of its free area along the web is covered by an impermeable web.

Preferably, a vertical partition parallel to the conveyor is provided in the vacuum chamber and is connected to an adjusting screw arranged transversely below the conveyor.

In front of the first support roller, a tensioning device abuts against the web material.

The application nozzles are preferably arranged on a beam which is movably supported by rollers on rails which are arranged above the conveyor transversely to the conveyor, with cleaning rollers arranged in one or both end regions of the rails which are arranged in the path of the application nozzle outlets and are provided with a soft surface.

The application nozzles may optionally be arranged on a pair of transverse beams which are connected by pivot levers to an articulated quadrilateral.

The sealing needle of the application nozzle is provided with a separating membrane separating in the application nozzle the lower space for the deposited material from the upper space of the movable coil, which is arranged in the working gap between the permanent magnet and the yoke.

Above the separating diaphragm, the closing needle is provided with coaxial diaphragm disks between which spacers are arranged and a pressure gas inlet opens into the upper space.

The application nozzles preferably consist of a housing and a nozzle between which a planar bearing surface is formed.

The thicknesses of the diaphragm disks are less than 1% of their diameter and radial slots are formed in the diaphragm disks.

The lower space is provided with a supply of coating material, which flows tangentially into this lower space.

In the application nozzle, the potted cores are provided with fixed coils, and a working gap is formed between the potted cores, in which a disc magnetic anchor connected to the closing needle is arranged.

The stationary coils in the application nozzle may optionally be housed in potted cores consisting of a base plate with a protruding inner core, on which a hollow cylindrical beach is provided with a conical converging annular collar, wherein an annular magnetic anchor is arranged between the annular collars. it decreases with decreasing radius and then decreases with decreasing radius. The largest cylindrical cross-sectional area of ​​the circular magnetic anchor is preferably equal to 0.5 of the magnetic cross-section of the hollow cylindrical shell.

A new and higher effect of the invention is that by approaching the application nozzles to the web material to which the desired pattern is applied by these application nozzles, the contour sharpness of this pattern is increased. The approach of the application nozzles is made possible by precisely guiding the strip material on the support rollers to which it is pressed by the vacuum applied in the vacuum chambers in which the support rollers are supported. The tensioning device abutting the web in front of the first support pulley also contributes to the precise guidance of the web. The adjustable vertical baffle housed in the vacuum chamber together with an impermeable belt mounted on the conveyor allows paint to be applied to a web material narrower than the conveyor. The arrangement of the application nozzles on a beam that can be moved transversely to the feed direction of the web material expands the capabilities of the device and allows the application nozzle post to be reduced. The cleaning rollers can then only be arranged in the end travel regions of the beam. The alternative arrangement of the application nozzles on a pair of crossbeams forming an articulated quadrilateral together with the pivoting levers is very simple and yet provides a variety of patterning options.

The applicator nozzle design of the present invention is characterized by the simplicity and minimum weight of the movable parts and thus the rapid response to control signals, which allows to reduce the duration of the transient effects when opening and closing the applicator nozzle and thus further enhancing the contour sharpness of the applied pattern.

The device according to the invention is shown in the drawings, wherein FIG. 1 is a cross-sectional view of the overall embodiment, FIGS. 2 and 3 show the vacuum chamber of FIG. 1, FIG. 4 a modified overall design, FIGS. 5, 8 and 9. 6 and 7 show details of the application nozzles, FIGS. 0 and 11 are side and plan views of the modified embodiment, FIG. 12 is a plan view of another embodiment, and FIG. 13 is a front view of the cleaning roller.

In the embodiment shown in FIG. 1, the web material is guided on the conveyor 2 under the beams J on which the application nozzles 8 are arranged. It will be appreciated that a plastic material conveyor 2 may also be used in place of the rubber conveyor, provided that the material has acceptable elongation. The sheet material 6 is placed on the conveyor 4 at the beginning 6 of its upper side and comes under the first beam 6 with application nozzles 8. Under the conveyor 2 there is a vacuum chamber J in which vacuum is maintained by suction line 6 and unknown exhaust fan. 10 kPa. The conveyor 2, together with the strip material 6 on it, is pressed by this vacuum towards the support rollers 8 and is guided in a precisely defined position with respect to the individual application nozzles 8. It is clear that the application nozzles 8 are arranged against the support rollers 8. When working with a web material whose width is substantially smaller than the width of the conveyor 2, it is possible either to cover the conveyor 2 next to the web material with impermeable belts J or to provide a vacuum chamber 10 with an adjustable vertical baffle 10 and to set the vertical baffle 10 sheet material. This vertical partition 60 can be adjusted by means of an adjusting screw 11 and in a direction transverse to the sheet material 6 and the vacuum chamber chamber 11 in which vacuum is to be maintained is adapted in this way to the width 6 of the sheet material.

The conveyor 4 runs after passing underneath the application nozzles 4 through the return roller 64, then passes the washer 13, which consists of washing nozzles 14 arranged above the conveyor 2 and a tank 6 arranged below the conveyor 2. Further, a suction device for drying the conveyor 2 may be provided. 1, not shown in FIG. The fixing of the web material 6 on the conveyor 2 provides a negative pressure acting in the region of the vacuum chambers J. Due to the precise pressing of the web material 6 on the support roller, it is possible to adjust the application nozzles g at a precise distance from the web material in the range of 0 to 5 mm.

A further advantage of this arrangement is that the paint applied by the application nozzles 8 by means of the vacuum inside the vacuum chambers can penetrate deep.

FIG. 4 shows a modification of the structure of the device according to the invention. Some second webs 6 have a very porous structure, so that pressing the webs under vacuum would only be possible at very high suction power. In such belt materials, particularly woven fabrics, it is more expedient to press the belt material mechanically, for example, such that the belt material is guided ppd over a carrier roll with a certain wrap angle. Here, the web material 6 is placed downstream of the deflection pulley 16 on the conveyor 4 and is already firmly pressed against the conveyor 2 at the first support roller 17, which is wrapped around the conveyor 2. On a further support plate 18, the web material 6 and the conveyor 2 are again deflected by an angle 19 and, due to the inherent tension in the web material 6, are applied to the support roller 18. It is essential that the web material 6 is under a certain tension before the first support pulley 17 provided by the tensioning device 20. A similar encirclement is present on all other support rollers 21. 22. 23. To prevent the web material 6 from loosening on the conveyor 2, a small vacuum chamber 2t is provided downstream of the last support roller 23, which pulls the web material 1 onto the conveyor 2. This vacuum chamber 2 may be omitted if the conveyor 2 is provided with needles and weight The web material 6 is sufficiently large that the web material 8 is pressed against the conveyor 2 by gravity and cannot slip.

The construction of the applicator nozzle 8 according to the invention is shown in FIG. 5. The permanent magnet 24 together with the yoke 25 creates a high intensity magnetic field in the annular gap 26. An annular gap 26 accommodates a movable coil 27 which is wound on a slotted, light metal frame 28 or a frame of non-slotted insulating material, e.g., glass fiber reinforced polyester resin. The latter embodiment is more advantageous in spite of the deteriorated heat dissipation of the glass fibers, since the stiffness of the light metal frame 28 decreases considerably due to the required slots. The slots are necessary in order to limit the radiation and short-circuit currents. The conical shape of the carcass 28 close to the clamping nut 29 reinforces the carcass structure 28, which is then not susceptible to vibration. The movable coil 27 is provided with two leads (not shown) through which the driving signals 27 are supplied to the movable coil 27. The clamping nut 29 connects the carcass 28 to the sealing needle 30 of the applicator nozzle 8. The diaphragm discs 31 between which the spacer sleeves 32 are clamped provide the linear guidance of the sealing needle 30.

The rubber or plastic separating diaphragm 33 separates the lower coating space 34 from the upper space 35 in which the movable spool 27 is located. The coating material is fed to this lower space 34 by a feed 36 of the coating material. A particular embodiment of the orifice of this coating material supply 36 will be explained in more detail with reference to FIG. 7. The nozzle 37 is pressed against the housing 39 by a flange 40 to the screws. The closing needle 30 only extends through a path 41 of a few tenths of a millimeter. To set and adjust this path 41, an adjusting screw 42 is provided opposite the locking needle 10. Through the planar bearing surface 43 between the nozzle 37 and the housing 39, the nozzle 37 can be precisely centered relative to the conical tip of the closing needle 10. In this way it is possible to achieve an accurate opening and tight sealing of the conical tip 54 in the bore seat 46 of the nozzle H. The dye in the lower space 34 is under a certain overpressure which is transmitted to the membrane 11 so that the forces to be exerted by the movable coil 27 can be considerably. To avoid these forces being so great, the upper space 35 above the separating membrane 33 is pressurized. Therefore, an inlet 48 of pressurized gas, most often air flowing in the direction of arrow 52, ​​flows into the upper space 35, the pressure of this pressurized gas corresponding to the pressure of the material deposited in the lower space 34. Small differences between the two pressures can be used accelerate the closing of the closing needle 30 or its opening. This pressurized gas exits from the upper space 35 through the annular gap 26 and cools the movable coil 27. The apertures 49 in the carcass 28 of the movable coil 27 allow pressure equalization on both sides of the carcass 28 and cooling of the back side of the carcass 28 by the outgoing compressed gas. This pressurized gas first flows into the working gap 50 between the permanent magnet 24 and the yoke 25 and from there

Even through the throttle bore 21 ^to free space. Through the throttle orifice 20, it is possible to adjust the flow of the pressurized gas to prevent excessive leakage. In front of the nozzle 21 is^nB An outlet aperture 22 is formed at the end of the bore 22, and the ratio of the length of the bore 22 to its diameter can be used to influence the beam of deposited material exiting the deposition nozzle 8.

The coating material exits the coating nozzle 8 at a speed of at least 10 m / s. The applicator nozzle 8 is at a distance 22 from the surface 54 of the sheet material 1, which is preferably in the range of 0.5 to 2 mm. As a result, a high viscosity deposited material is penetrated into the sheet material 1 deep enough. In addition, this treatment produces sharper contours of the applied pattern.

FIG. 6 shows in detail the diaphragm disk 31, which is made of a thin metal sheet with a thickness of less than 1% of the diameter of the diaphragm disk 56. ⁱⁿ radial slots 57 are formed which allow the center 58 of the diaphragm disk 21 to deflect by a few tenths of a millimeter with little force.

Figure 7 illustrates in more detail the outlet 36 of the coating material into the lower chamber 21. Because there are some cleaning problems with all spray nozzles, the coating feed 36 is tangential, thereby achieving a circular flow when cleaning the lower chamber 34 which greatly contributes to this cleaning.

By using a radial orifice of the feed material inlet 16, vortex areas and dead spaces arise at the sides of the orifice so that the cleaning of the surrounding area of ​​the orifice is imperfect.

Fig. 8 shows a further variation of the applicator nozzle design 8. The design of the lower chamber 34 and the nozzle 37 of the applicator nozzle 8 is the same as in Fig. 5. The clamping of the diaphragm disk 21 of the separating diaphragm 33 and spacer 32 is similar to Fig. 5. and is secured by a nut 60 and a threaded ring 61 with a notch on the face that is; screwed into housing 39.

A pressure gas supply 48 opens into the space above the separating membrane 33. The deposited material is fed to the lower space 34 through a feed 36 of the deposited material. The closing needle 30 is here controlled by a disc magnetic anchor 62, which is made of dynamo plates. Two or more circular plates of low-thickness dynamo plates are joined together into a thin beam that moves in the direction of arrow 64, thereby achieving closing and opening of the applicator nozzle 8. Pot core 63. They are made of ferrite material, which greatly reduces eddy currents and thus losses. Inside these cup cores 62 are fixed coils 65. Upon opening of the application nozzle 8, the upper fixed coil S5 is excited. the lower stationary coil 65 is de-energized. When closing the application nozzle 8, the lower stationary coil 65 is energized. The upper stationary coil 65 remains free of current. A set screw 66 extends through the cover plate 67 to precisely adjust the path of the shut-off needle 30. The position of the potted cores 63 is adjusted by screws 68 which abut the ends of the potted cores §2. The tightening bolts 62 allow for final locking of the potted cores 62 in the housing 70. The pressurized gas supplied by the pressurized gas supply 48 into the space above the separating membrane 22 gap 22 and hence openings 22 ^d° ambient atmosphere. An advantage of the embodiment of FIG. 8 from Comparison 3 of the embodiment of FIG. 5 is that despite the relatively small weight of the disc magnetic armature 62, high contact forces can be achieved, wherein the stationary pins 65 can be connected by rigid leads that are not subjected to bending stress. The ratio of the conductors of the stationary coils 65 can be dimensioned such that the heat dissipation generated by these stationary coils 65 and the problems of dissipation of this heat are substantially reduced.

The advantage of the embodiment of FIG. 5 compared to the embodiment of FIG. 8 is that the ratio of force to the mass of the needle can be increased arbitrarily by increasing the current flowing through the movable coil 27. However, dissipation of heat from the movable coil 27 must be ensured. 8 is therefore selected according to the operating conditions. The movable coil 21 of FIG. 5 or the stationary coil 65 of FIG. 8 is excited by rectangular current pulses.

A high intensity current is passed through the coil 21E for a few hundredths to tenths of a second, and then approximately ten times less continuous current. In this way, very high acceleration values ​​can be achieved in the embodiment according to FIG. 5 and the application nozzle 8 is particularly suitable for producing fine patterns. There are sufficiently long intervals between the individual energies of the field current, during which a substantially smaller continuous current flows through the moving coil 27. Because in the embodiment of FIG. 8 there are considerably better heat dissipation conditions, but the magnetic force cannot be increased despite the saturation of the disc magnetic anchor 62. Although high acceleration values ​​cannot be achieved here, the applicator nozzle 8 can be opened and closed more frequently per unit of time. The construction of the application nozzle 8 of FIG. 8 can be switched continuously at a repetition rate of 2 to 3 kHz. That is, the closing needle 30 of the applicator nozzle 8 opens and closes approximately 2,000 to 3,000 times per second. This mode of operation of the applicator nozzle 8 is intended to allow mainly the printing of halftones. It is known in silk screen printing that true halftones cannot be printed with rotary templates. Halftones are achieved in silk screen printing by creating large holes in the stencil. However, the various large holes in the stencil have the drawback that the tone value is greatly distorted during the stencil manufacture, which excludes the achievement of high-quality halftones. However, the fast operable spray nozzle 8 can be opened for a longer or shorter time at a constant opening frequency, or at a constant opening time, opening at a higher repetition rate, allowing different amounts of coating material, such as paint, to be applied per unit time. the desired shade of color.

Referring to FIG. 9, another embodiment of the application nozzle 8 is shown. The stationary coils 65 are housed in hollow cylindrical shells 74 which are closed on one side by base plates 75. The base plate 75 is provided with an inner core surrounded by a stationary coil 65. the plate 75 is glued to the contact surface 76 with a hollow cylindrical shell 74 which can be separated from the base plate 75 by an insulating insert, for example of paper, to reduce eddy currents. The outer edge of the hollow cylindrical shell 77 is adjoined by an annular collar 77 which converges conically toward the circular magnetic anchor 78.

The thickness of the annular magnetic anchor 78 increases with the edge toward the edge and then decreases again. For optimum utilization of the material of the circular magnetic anchor 78, there must be a constant magnetic saturation. Therefore, in the region between the edge 79 and the first breaking point 81, the thickness of the circular magnetic anchor 78 increases considerably, because the magnetic flux increases here as the radius decreases. In the region between the first breaking point 81 and the second breaking point 82, the total magnetic flux is already constant, so that also the cylindrical cross-sectional area of ​​the circular magnetic anchor 22 »d^E however, this means that the thickness of the circular magnetic anchor 78 in this region still has to increase with decreasing radius, since the condition 2n * h must be fulfilled. h = constant and the radius decreases. From the second breakpoint 82 towards the axis 80, the thickness of the circular magnetic armature 78 decreases again due to the reduced magnetic flux. The central region 83 of the circular magnetic anchor 78 is already of a constant thickness and serves to attach the circular magnetic anchor 78 to the closing needle 30.

By means of the illustrated profile of the circular magnetic anchor 78, a high pulling force can be achieved with a minimum weight of the circular magnetic anchor 78. At each point of the radius of the circular magnetic armature 78, the profile is such that the circular magnetic armature 78 has an almost constant magnetic saturation at a given magnetic flux. The maximum cylindrical cross-sectional area of ​​the circular magnetic anchor 28 concentric to the axis 80 is approximately half the cross section available for the magnetic flux in the hollow cylindrical shell 74 and the base plate 75. The air gaps 84 between the circular magnetic anchor 78 and the base plate 75 and the annular collar 77 is the choice? so that the closing needle 30 can move with a stroke of several tenths of mm. The stationary coil 65 is sized such that the circular magnetic armature 78 is just magnetically saturated and that the stationary coils 66 do not overheat too much. A further advantage of the described embodiment of the circular magnetic anchor 78 is that the masses of the circular magnetic anchor 78 are shifted towards the axis 80, whereby the natural frequency of the circular magnetic anchor 78 also increases.

When the material is applied by the controlled application nozzles 8, a stationary beam 3 with application nozzles 8 can be arranged above the web material and the web material 8 can be moved under the application nozzles 8. A very large number of application nozzles 3 is required for corresponding fine pattern resolution. the whole device is very bulky and expensive. Especially when relatively fast operating nozzles 8 according to the invention are used instead of the usual application nozzles 8, which are relatively expensive, it is expedient to make better use of the application nozzles 8, i.e. to give them their own movement to cover a larger portion of the web. Such an arrangement requires a considerably smaller number of applicator nozzles 8 and allows the application of fine patterns with the need for fewer transmission devices, ie sensors, preamplifiers and power amplifiers. Possible embodiments of such a device are shown in Figures 10 to 12.

According to FIG. 0, the web material 6 is guided by a conveyor 2 beneath the beams 8 with application nozzles 8. The conveyor 2 is guided through two return rollers 94, which are arranged on the apparatus frame 95 . After printing, the web 6 is lifted from the conveyor 2 and fed to the dryer 96.

The conveyor 2 may be of wire mesh and the web material 6 may be pressed against the conveyor 2 by means of vacuum chambers (not shown) which are arranged below the conveyor 2.

In the embodiment shown in FIGS. 10 and 11, rails 99 are provided transverse to the feed direction of the web material, indicated by the arrow 101. In FIG. ^on The rollers 97 bear the support beams. The beams 8 can be moved by the rollers 97 in the direction of the arrow 98, i.e., towards the feed direction of the web material 6. The rails 99 also extend over the lateral areas 100 that lie on either side of the web material. In these side regions 100 there are ink collecting tanks, i.e. tanks into which the paint or the purification water can be drained during cleaning and color change.

The beams 8 are guided across the web material 6 in the direction of arrow 98 from the initial position shown in FIG. Depending on the program, the application nozzles 8 spray the application material onto the web material. After the beams 8 pass over the web material 6, the web material 6 is moved in a stepwise direction in the direction of arrow 101. The size of this step is freely adjustable and is chosen according to the design of the application nozzles 8 and patterned according to the desired fineness. Thereafter, the beams 4 are returned to their initial position and, during this reversal, print the web material 6 again. The application nozzles 8 are controlled by signals from data or control lines (not shown). An advantage of this embodiment of the invention is that only a small number of applicator nozzles 8 are required to print the large widths of the web material. The printing speed that can be achieved in this case is comparable to that of conventional carpet printing machines, thus in the range of 3 to 10 m per minute. Investment costs are relatively low.

Referring to FIG. 12, the web material 4 is bridged by transverse beams 103, 106 with applicator nozzles 8 that can be moved in a stepwise direction transverse to the web material 8 in the direction of the arrow 102. Each transverse beam 103, 106 can, of course, carry a plurality of applicator nozzle rows 8, but for better understanding, only one applicator nozzle row 8 is shown in FIG. The transverse beams 101, 80 are connected to the articulated quadrilateral by means of the pivoting levers 104, so that when the transverse beam 103 moves in one direction, the other transverse beam 106 moves in the opposite direction.

This construction reduces the stress on the base of the device, since the center of gravity of the articulated quadrilateral does not move. Each application nozzle 8 on the crossbeam 103, 106 in its movement exceeds only a fraction of the width 105 of the web material. This path can be, for example, 2.5 cm, so that the joints 107, 108 of the transverse beams 103, 106 are displaced transversely to the web material by only 2.5 cm, thus saving the space required for the displacement of the transverse beams 103, 106. The pivoting levers 104 are rotated by means of a common linkage 110 and a hydraulic cylinder 111. After the short stroke of the crossbars 103, 106 has been completed, the conveyor 2 together with the web material 8 is moved in a stepwise direction in the direction of arrow 109.

In Fig. 3, there is shown a device for cleaning the application nozzles 8. Here too, the beam 8 is supported by rollers 97 on rails 99 which are anchored on both sides of the device in the foundations 113. The web is moved by a conveyor 2 as described above. or may lie on the printing table 118 as shown in FIG. 13. Next to the printing table 118, a shaft is formed on one or both sides in which the cleaning roller 115 is rotatably mounted. The surface of the cleaning roller 115 may be provided with a foam coating. When moving beam 3^se the ends of the application nozzles 8 rub against the cleaning roller 115 and any dirt or paint drops are wiped off the surface of the cleaning roller 115. In order to remove dirt and paint residues from the cleaning roller again, water nozzles 116 and squeezing rollers 117 are provided in this cleaning roller 115. The squeezing rollers 117 can be pressed against the cleaning roller 115 by lever assemblies 119. The water jets 116 and the application of the squeezing roller 117 can be automatically derived from the movement of the beam 3. The movement of the nozzle beam 3 continues beyond the channel 114 above which the beams 3 can also stop. By means of the channels 114 it is possible to replace the application nozzles 8 with minor repairs.