CA1091105A - Method and an apparatus for the application of pattern onto goods, especially onto a web as well as an injection jet - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A method is provided herein for applying patterns to a substrate The method includes the steps of spraying a solution of a solution which creates pattern onto the substrate, the solution being sprayed into the material directly in the form of a plurality of jets, the jets being emitted from nozzles adjustably disposed in the immediate vicinity of the substrate surface, the nozzles being opened and closed pursuant to a predetermined program. In this way high quality sheet goods may be prepared with patterns formed thereon with the aid of the highly directive spray nozzles without the use of a printing screen.

Description

--' 1091105 The present invention relates to a method for applying patterns to a substrate, especially a sheet of fabric or the like, as well as to a spray noz~le to be used for this purpose.
In conventional printing systems a pattern is generally applied to a substrate by way of a suitably apertured screen. Recently, attempts have been made to form patterns on sheets with the aid of highly directive spray nozzles without the use of a printing screen. Heretofore, however, the quality of goods treated in this manner has been less than satisfactory.
An object of a main aspect of the present invention is to provide an improved method for patterning a substrate by direct-spray technique.
In accordance with a main aspect of the method of the present in-vention, the spray nozzles are positioned in the immediate vicinity of the suitably supported substrate.
By one aspect of this invention, a met hod is provided for apply-ing patterns to a substrate, the method comprising: spraying a solution SVBs7~of a ~q~b~n which creates pattern onto the substrate, the solution being sprayed directly onto the material in the form of a plurality of ~ets, the jets being er~tted from nozzles ad~ustably d~sposed in the immediate vicini-ty of the substrate surface, the nozzles being opened and closed pursuant to a predeterminad program.
By a variant thereof, the program is sensed from a matrix; and wherein the sensing commands are converted into control pulses for the nozzles.
By another aspect of this invention, a method is provided for applying a pattern to a continuous substrate web of material having a pile surface by spraying a solution of a substance which creates a pattern there-on into the pile of the material, the solution of the substance being sprayed onto the material directly in the form of a plurality of ~ets which issue from a respective nozzle ad~ustably disposed near and substantially ,, ` 1 - 1- ~; ' , l ... .

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touching the pile surface of the material; the nozzles being opened and closed by pursuant to a preselected program.
By a variant thereof, the program is derived by scanning a master pattern, thereby to obtain information which is converted to commands for operating the nozzles.
By one variant of these aspects of this invention the substrate is held in a precisely defined position relative to the nozzles.
By another variant, the substrate is located on a conveyor and is moved past the nozzles.
By yet another variant, the substrate is located on a conveyor and is moved past the nozzles, wherein the substrata is porous and wherein suction is exerted upon the substrate or upon the conveyor in the region of the nozzles.
By a further variant, the substrate is located on a conveyor and is ved past the nozzles, wherein the conveyor or the substrate is pressed along successive sections of its surface onto respective support rollers.
By yet another variant, the substrate is located on a conveyor and is moved past the nozzles, wherein the conveyor or the substrate is ~-pressed along successive sections of its surface onto respective support

2 rollers and further wherein the substrate is tensioned upstream of the first support roller.
~ By a still further variant, the discharge velocity of the ~ets from the nozzles is at least 10 meters per second.
By yet another variant, the substrate is located on a conveyor and i8 moved past the nozzles, wherein the nozzles are displaced across the substrate transversely to the motion of the substrate.

f ,' .: ' , ' ' ' ' -``` 11)91105 By a still further varlant, the substrate is located on a conveyor and is moved past the nozzles, vhereln the conveyor or the substrate is led in tension around part of the surface of consecutively disposed backing rollers.
By yet a still further variant, the substrate is located on a con-veyor and is moved past the nozzles, whe~ein a plurality of the nozzles are combined in an array, the array being moved as a unit across the direction of travel of the substrate and through a distance exceeding the width of the substrate; the article being intermittently advanced after each tra-verse, and the array being returned to its starting position.
By still another variant, the substrate is located on a conveyor and is moved past the nozzles, wherein a plurality of the nozzles are com-bined in an array, the array bèing moved as a unit across the direction of travel of the substrate and through a distance exceeding the width of the substrate; the article being intermittently advanced after each traverse, and the array being returned to its starting position, herein the array of nozzlès is mounted on rollers running on rails extending across the direc-tion of travel of the article.
By a further-variant, the substrate sprayed i8 a printing ink or dye.
In order to provide a wide range of color shades, the intensity of the spray may be made variable by mounting each nozzle on a wall of a dye chamber in which printing liquid is received under electromagnet~cally ad~ustable pressure. Advantageously, with the substrate continuously mov-ing in a predetermined direction past an array of printing nozzles, these nozzles are distributed in one or more row~ over the width of the substrate and are limitedly movable in a direction transverse to the substrate motion, under the control of a programmer, in order to race mutually complementary strokes of a certain color in a given pattern.

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In the accompanying drawings:
FIG. 1 is a longitudinal-sectional view of a printing machine for carrying out the method of one aspect of this invention;
FIG. 2 is a cross-sectional view of part of the machine shown in FIG. l;
FIG. 3 is a view similar to FIG. 2 illustrating a modification of a machine for carrying out the method of another aspect of this invention;
FIG. 4 is a diagrammatic elevational view (appearing on the same sheet as Figure 1) of an alternate embodlment of a machine for carrying out the method of another aspect of this invention;
FIG. 5 is an axial sectional view, drawn to a larger scale, of an electromagnetic ink applicator according to another aspect of this in-vention adapted to be used in a machine as shown in the preceding Figures;
FIG. 6 is a plan view and FIG. 7 is a sectional view showing de-tails of the applicator of FIG. 5;
FIG~. 8 and 9 are views similar to FIG. 5, showing modifications of the ink applicator adapted to be used in a machine for carrying out the method of an aspect of the present invention;
FIG. 10 i8 a diagrammatic side-elevational view of a machine for carrying out the method of another aspect of this invention, similar to that shown in PIG. 1 but provided with additional features;
FIG. 11 is a top plan view of a machine shown in FIG. lO;
FIG. 12 is a view similar to FIG. 11, illustrating a modification of a machine adapted to be used in a machine for carrying out the method of an aspect of the present invention;
FIG. 13 is a fragmentary, diagrammatic cross-sectional view of a printing machine of the generay type adapted to be used in a machine for carrying out the method of an aspect of the present invention~and as shown in preceding Figures, but illustrating another detail; and , Cl 4 _ . , . . ~ , ' , . ' '' , - ` 1091105 FIG. 14 is a diagrsm of a control circuit for controlling an electromagnetic ink applicator as shown in FIGS. 5 - 9, adapted to be used in a machine for carrying out the method of an aspect of the present inven-tion, FIG. 1 shows a substrate 1 which is transported by an endless con-veyor 2 past several sets of dyestuff applicators 3. Conveyor 2, led around rollers 12, may consist of woven wire mesh or of a perforated sheet of polymeric material such as, for example, vulcanized rubber or plastic of limited longitudinal extensibility. The substrate l,which may be a web of fabric continuously drawn from a supply roll (not shown), enters the machine at 4 and passes between the conveyor 2 and the applicators 3. Be-low the conveyor, in line with each set of applicators, there is provided a suction box 5 in which a partial vacuum is produced by a blower (not shown) whose low-pressure side communicates with a duct 6. The magnitude of this vacuum may range between 100 and 1000 mm of water column substanti-ally equivalent to 0.01 - 0.1 atmosphere. This partial vacuum firmly holds the conveyor 2 together with the overlying substrate 1 onto supporting rollers 7, thereby maintaining a well-defined separation between the sub-strate and the applicator nozzles 8. This separation may range between several millimeters and a fraction of a millimeter; in an extreme case the nozzles could even tough the substrate. Advantageously, as illustrated, the nozzles 8 are precisely aligned with respective supporting rollers 7.
In order to accommodate substrates of widely different widths, an air-impermeable cover 9 may be disposed on the suction box 5 alongside a narrower substrate as shown in FIG. 2. Alternatively, a lateral partition 10 transversely shiftable by a leadscrew lla can be disposed in the suc-tion box (see FIG. 3) to confine the vacuum to a space 11 directly below the substrate.
FIG. 1 further shows a washing station 13 traversed by the con-veyor after it passes around the outlet-side roller 12, this station com-r~ > ~

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prising a set of sprinklers 14 above the lower run of the conveyor and a trough 15 below lt. The trough could also be provided with a nonillustrated suction device to expedite the drying of the conveyor.
The use of a partial vacuum to hold the substrate to its carrier in the region of the spray nozzles has the added advantage of promoting, in a manner known per se, the penetration of the dyestuff into the inter-stices of the substrate.
,'~r' FIG. 4 shows a modified printing machine particularly designed -. for coarse fabrics or other wide-mesh substrate which would require a high degree of suction in order to be held firmly onto its conveyor or other support. In such a case it is advantageous to guide the substrate 1 along ~ .
~ an upwardly convex path defined, downstream of an entrance roller 16, by a ~,...................... .
set of support rollers 17 - 23 aligned with respective spray nozzles. At - each roller 18 - 23, the substrate is deflected downwardly by a small angle 19 and thus held under tension against that roller. This tension may be imparted to the substrate, upstream of the first deflecting roller 16, by a friction brake 20 and may be maintained downstream of the last roller 23 by a suction box 5 similar to those described above. Such a suction box could be omitted if the conveyor 2 is studded in a manner known ~ se and if the weight of the substrate is high enough to hold that substrste onto the conveyor with a sufficient pressure to prevent its shifting on the ; studded surface.
FIG. 5 shows an advantageous dyestuff applicator adpated to be ; used in a machine for carrying out the method of an aspect of the present invention. This applicator comprises a permanent magnet 24 forming a cen-tral core integral with a flange serving as a cover for an annular space 50 surrounding that core. The flange of magnet 24 rests on a ferromagnetic housing 25 forming a narrow annular gap 26 with the lower end of the core.
An annular coil 27 coaxially surrounds that lower end and is vertically .' ', C ~ - 6 -'' ' ' , ' ' ' ` ' ' 9ilOS
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`~; movable within the gap 26 while being held on a downwardly tapering carrier ....
~n 28. This carrier, which has a very small wall thickness, may consist of light metal or of plastic material e.g., glass-fiber-reinforced polyester.
In order to minimize any currents, the carrier should be slitted if made of metal. It is therefore preferable to use a resinous carrier, despite its lower thermal conductivity, since the absence of a slit enhances its mechanical stability. This stability is further improved by the frusto-conical shape of the lower part of the carrier body terminating in a base ~;":
29 of small radius to which a depending control needle 30 is attached.
10 Needle 30 is secured to a pair of vertical membranes 31 which are clamped s in position, e.g. as shown in FIG. 8 described hereinafter, in order to be ~; held centered on the vertical axis of the applicator, a high-strength mag-netic field (e.g. on the order of 15,000 gauss) may be easily maintained ~:~ in the annular gap 26.
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As seen in FIG. 6, each membrane 31 is formed with a set of radial ~- slots 57 designed to facilitate a deflection of its center 58 relatively . ~ to its clamped rim 59. This allows the needle 30 to be raised or lowered ,~ by several tenths of a millimeter with only a minimum force. The membranes advantageously consist of thin sheet metal whose thickness should not ex-20 ceed 1% of their diameter 56.
Annular space 50 is vented to the atmosphere at a port 51 and . ~ ,, .
` communicates, via gap 26, with a space 35 surrounding the coil carrier 28.
~ Space 35 extends into the region between the membranes 31, owing to the ; ~- presence of the radial slots 57. A diaphragm 33 of rubber of plastic .~ material separates this space in a fluidtight manner from a dyestuff cham-., . - .
~ ber 34 which opens into a bore 46 of a nozzle=45 integral with a bottom .
plate 37 closing the chamber 34 from below. Plate 37 lies flat against .: ~
the underside 43 of a peripheral wall 39 of chamber 34 onto which it is clamped by screws engaging a retaining ring 40; a packing ring 38 in a groove of surface 43 shields the chamber 34 against the atmosphere. Dye-. ~ ~, ~ .

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stuff can be admitted into chamber 34 via an inlet 36 which, as best seen in FIG. 7, opens tangentially into the chamber to facilitate a cleaning ? - thereof by a rinsing fluid circulatin~ in the direction of the arrows. With .
a radially extending inlet there would be a tendency to form pockets in which the cleansing action of the rinsing fluid would be greatly dimlnished.
Needle 30 terminates in a cone 44 which ad~ustably constricts the bore 46 leading to the orifice 53 of nozzle 45. The outlet end 52 of this orifice is separated from a nap 54 of the substrate by a small distance 55 of, say, 0.5 to 2 mm. The dyestuff in chamber 34 is preferably discharged from orifice 53 at a velocity of at least 10 meters per second; this speed and the small distance 55 insure a penetration of the nap 54 even by a relatively viscous dyestuff with sharp tracing of the strokes of the pattern to be formed thereon. In order to maintain the injection pressure of the dyestuff within chamber 34, a back-up pressure is created in space 35 by the admission of a stream of compressed air 47 into that space through an inlet 48. The two pressures should be equal but a slight difference there-between may be utilized to accelerate the electromagnetic displacement of needle 30 in a downward or an upward direction to increase or reduce its throttling effect upon the outflow of dyestuff. The compressed air leaves the space 35 by way of vent 51 and, in passing through the gap 26, helps c-ol the electromagnetic coil 27 which is energized over nonillustrated leads by a circuit described hereinafter with reference to FIG. 14. Coil .. ..
~`~ carrier 28 has apertures 49 designed to equalize the pressure inside and ~;~ outside its body, these apertures also enabling part of the cooling air-.~.,., ~;
` stream to circulate along the inner coil surface. Port 51, which may be ~ one of several outlets, may be provided with conventional throttling devices, ;~ e.g., screws or valves designed to ad~ust the air pressure within the appli-~ .., ,,~
cator and to slow the escape of the admitted air. The stroke 41 of needle `- 30 is ad~ustable by a setscrew 42. The shape of tho spray leaving the ,~ .
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nozzle 45 i8 determined by the ratio of the length of orifice 53 to its dismeter.
,- FIG. 8 shows a modified applicator adapted to be used in a ma-~ .
- chine for carrying out the method of an aspect of the present invention `~` whose lower portion, including dyestuff chamber 34 and nozzle plate 37, is practically the same as in FIG. 5. Membranes 31 and 33 are held in posi-,, .
~`'` tion by concentric annular spacers 32, also shown in PIG. 5, with the aid of a hexagonal nut 60 on a threaded upper extremity of needle 30 and a sur-rounding notched nut 61 with external threads screwed into a recess of , . . .
`- 10 peripheral wall 38. The upper end of needle 30, traversing a bore 71 in a plate forming the bottom of a chamber 72, is secured to a ferromagnetic foil 62 preferably of the laminated type. Foil 62 constitutes the armature of ,~ a pair of confronting electromagnets with toroidal cores 63 and coils 65, . ,.
the cores being separated by a narrow axial air gap within which the foil 62 can oscillate vertically as indicated by an arrow 64. These cores ad-vantageously consist of ferrites minimizing the flow of eddy currents and the losses of energy resulting therefrom. The coils 65 of copper wire can ~ ",, ,~ be alternately energized to raise or to lower the needle 30. The stroke of the needle is limited by a setscrew 66 threaded into a cover plate 67 which rests on a peripheral wall 70 and carries grub screws 68 which, to-,. gether with similar screws in the associated bottom plate, serve for a i precise adjustment of the position of the cores. This position can be -fixed with the aid of setscrews 69. The high-pressure air entering the space 72 via inlet 48 and gap 71 escapes through ports 73 which could , , .
again be provided with throttling devices (not Rhown).
~ The embodiment of FIG. 8 has the advantage, compared with that ;- of FIG. 5, that large forces can be developed with a small armature mass and that the coil assembly 65 is stationary so as to be energizable by fixed leads which are not damaged by the high-speed needle movements. More-' .' , _ g _ .

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-- " 1(191105 over, the coils can be made as large as necessary to dissipate the develop-in8 heat.
On the other hand, the embodiment of FIG. 5 has the advantage that the ratio of applied force to movable mass can be made as large as de-sired through the use of sufficient energizing currents for the coil 27.
This requires, of course, the sufficient heat be dissipated by the struc-ture. Thus, one or the other type of applicator may be preferred under given circumstances. In either case, the electromagnetic winding should -be energized with short rectangular pulses, e.g. of a duration of several tenths or hundredths of a second, followed by a constant current of a mag-nitude reduced by a factor of 10. This mode of energization enables high accelerations with the applicator of FIG. 5 whose nozzle can thus be used for the tracing of fine details, albeit with relatively large intervals be-~ tween pulses during which only the constant holding current flows through i ~'~ the coil 27. Since the construction of the nozzle of FIG. 8 provides bet-~ ter cooling but acceleration is limited by the saturation of the foil 62, - this applicator cannot respond as quickly, but is nozzle can be opened and closed more frequently within a given time interval. In principle, the con-~ . .
struction of the nozzle of FIG. 8 i8 intended for a periodic opening and closure at a rate of 2000 to 3000 reciprocations per second. Such an opera-tion facilitates particularly the printing of half-tones which is very dif-ficult to achieve with conventional printèrs of the rotary-screen type.
In the case of a printing screen, different color shades are produced by the use of larger or smaller screen apertures. This technique, however, in-herently falsifies the relative values of the color shades so that true half-tones cannot be achieved. On the other hand, a quick-acting spray nozzle adapted to be used in a machine for carrying out the method of an f~ aspect of the present invention enables the nozzle orifice to be held open - for longer or shorter periods at a frequency which can be held constant or varied at will, in conformity with the desired shade, so that precisely .. . .
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measured quantities of dyestuff can be sprayed onto a unit area of the substrate.
~; FIG. 9 shows another applicator adapted to be used in a machine for carrying out the method of an aspect of the present invention which is generally similar to that of FIG. 8 but wherein the coils 65 are encased in differently shaped holders 74, 75 of ferromagnetic material. The inner holder portion 75 forms a flanged core, similar to that shown at 24 in FIG.
5, surrounded by the coil 65 and bonded at 76 to the outer annular portion : 74. An insulation layer, e.g. of paper, may be inserted at the ~oint 76 to prevent the flow of eddy currents. At 77 the holder portion 74 converges frustoconically toward an armature 78 replacing the foil 62 of FIG. 8.
Armature 78 has an outer peripheral ridgh 79 and spreads verti-cally toward the axis 80. Thus, the annular cross-section of the armature along a cylinder surface centered on that axis increases sharply up to a , .
point 81 and then only slightly to a point 82 whereupon it decreases with shorter radii. A ~mall disc 83 of constant thickness forms the center of the armature and serves to secure it to the needle 30.
This shape is designed to produce large forces with small movable masses. The effective cross-section of armature 79 perpendicular to the flux, i.e. along cylinders of different radii centered on axis 80, is so chosen that the degree of saturation is substantially uniform throughout the armature body. These cross-sections are preferably only about half as large as those which the flux traverses in the coil holders 74, 75. Air gaps 84 between the armature 78 and the coil holders 74, 75 are ~ust tight enough to permit a needle stroke of a few tenths of a millimeter. The coils 65 should be so dimensioned that the armature 78 can reach its satura-tion without excessive heat development in these coils. A further advantage of thiQ armature configuration is the fact that its mass is concentrated closer to its axis (as compared with a disc-shaped body of constant height, e.g., foil 62) so that its natural frequency shifts to higher values.

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'' --" 109:1105 In order to imprint substrates with ~ets trained upon them, as described hereinabove, a nozzle carrier can be mounted fixedly above the _ substrate which can be moved underneath the nozzles. With a pattern whose design consists of many fine lines, a large number of such stationary noz-zles is required so that the system becomes bulky and expensive to manufac-ture and operate. It is therefore advantageous to use nozzles, especially those of the fast-acting type described above, which are themselves movable so that a single nozzle can spray a substrate zone of considerable width.
Such an arrangement greatly reduces the number of nozzles required and also simplifies the associated equipment including pattern readers coaeting with a matrix, preamplifiers and power amplifiers designed to convert sensing commands into control pulses for the nozzles. FIGS. 10-12 show such an arrangement designed to produce intricate patterns by relatively simple means in a machine for carrying out the method of aspects of this invention.
According to FIG. 10 the substrate 1 is again advanced, as in FIG.
1, on an endless conveyor 2 (or possibly on a stationary support table) past several sets of dyestuff applicators 3 operating in the above-discussed manner. Conveyor 2 is shown led around rollers 94 mounted on a base 95.
The imprinted substrate is received in a drying chamber 96.
Suction boxes 5, as shown in FIG. 1, can again be disposed be-neath the upper run of the perforated conveyor.
As shown in FIGS. 10 and ll,rails 99 rigid wi th base 95 extend transversely across the substrate 1 and are engaged by rollers 97 from whose shafts the applicators 3 are suspended. The nozzle arrays can thuE be dis-posed as indicated by arrows 98, in a direction perpendicular to the direc-tion of travel 101 of the substrate. The rails extend on each side of the substrate beyond the conveyor 2 so as to overhang lateral receptacles 100 designed to receive residual dyestuff in the event of a color change or rinse water after completion of a printing operation.
The shifting of the nozzles in the direction of arrows 98 is ., . ~ . .
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accompanied by a modulation of their ~ets according to a predetermined program..Upon completion of a traverse, the substrate 1 is advanced in the direction 101 by a predetermined increment of movement which can be selec-ted according to the layout of the nozzles and to the desired complexity of the pattern, The applicators 3 can then be returned to their starting point and, in the course of this reverse stroke, again irrigate the sub-strate 1 with dyestuff. The programmer and the associated control circuits - for the opening and closure of the noæzles have not been illustrated. Print-ing speeds comparable to those of conventional carpet-printing machines, in a range of 3 to 10 meters per minute, can be realized in this manner with the aid of considerably less expensive equipment.
According to FIG 12, the substrate 1 is spanned by nozzle-bars 103, 106 which are articulated to cross-levers 104 to form parallelogramatic linkages therewith. EAch bar 106 may, of course, carry more than a single row of nozzles. A piston rod 110 of a hydraulic servomotor 111 controls these linkages so as to make their nozzle bars move alternately in opposite directions, as indicated by an arrow 102, again transversely to the direc-~- tion of motion of the substrate represented by an arrow 109. The stroke of the ~oints 107 and 108, and therefore that of each individual nozzle, is only a small fraction of the width 105 of the substrate, amounting for example to 2.5 centimeters while the width 105 may be on the order of me-ters. The intermittent advance of the substrate is again times to occur at the end of any stroke.
FIG. 13 shows an arrangement for cleaning the nozzles of an ap-plicator 3 in a machine for carrying out the method of aspects of this in-vention which is generally similar to that shown in FIGS. 10 and 11, except that the conveyor 2 has been replaced by a support table 118. At one or both sides of this table there is provided a cylinder 115 whose surface may be covered by an absorbing foam layer and which contacts the nozzles whenever the applicator 3 moves across it on rails 99. These rails are lO9ilO5 provided with end mountings 113 separated from the table 118 by a channel 114 which provides easy access to the nozzles for purposes of inspection, replacement or minor repairs. Residual dyestuff and other matter removed from the nozzles by the cylinder 115 are taken off by stripper rolls 117 which are pressed onto the underside of that cylinder with the aid of mova-ble arms 117. Sprlnklers 116 flanking the cylinder 115 can be actuated automatically, in certain inoperative positions of the applicator block 3, to irrigate the cylinder surface while the stripper rolls are simultaneous-ly moved upwardly into contact with the cylinder.
10FIG. 14 shows a circuit arrangement for the rapid energization of .~ .- the electromagnetic coils in the applicators of FIGS. 5 - 9 which are adap-ted to be used in a machine for carrying out the method of an aspect of the present invention. These coils are represented in FIG. 14 by an induc-tance 210 inserted between a PNP power transistor 202 and an NPN power transistor 203. Transistor 202, when conducting, briefly connects the coil 201 to positive potential of, say, +70V simultaneously, of course, the other power transistor 023 must also conduct in order to complete a circuit to ground by way of a low-ohmic resistor 204.
Transistor 202 conducts only for a short period, e.g. of 0.5 ms, causing a steep rise of the current in coil 201. Upon the cutoff of this transistor the coil is energized via a diode 205 with a voltage of +8V.
This voltage suffices to maintain a holding current in the coil 201 as long as the transistor 203 conducts. Upon the cutoff of this transistor it is desirable that the coil 201 be de-energized as quickly as possible.
For ~his purpose the end of the coil proximal to the transistor 203 is con-nected by way of a resistor 206 and a diode 207 to positive potential. In this way the ~energy stored in the coil is returned to the supply rather than being wastefully converted into heat.
The two power transistors 202 and 203 operate as follows:
A terminal 208 receives a rectangular pulse measuring the period , .

1()91105 during which the coil 201 is to be energized. This pulse, passing through a resistor 209, energizes a light-emitting diode 210 of an optical coupler 211. A light-responsive transistor 212 in coupler 211 thereupon sub-stantially grounds an input 213 of a Schmitt trigger 214 for the duration of that pulse. During this interval the output 215 of Schmitt trigger 214 carries a si~nal fed on the one hand to the base of an NPN pilot transistor 217 and on the other hand to a second Schmitt trigger 228. Pilot transis-tor 216, which is normally conductive, is blocked by this signal and drives the base of power transistor 203 positive, causing it to conduct. The second Schmitt trigger 218 has an inverting output 228 which at this point carries a voltage tripping a monoflop 220 whose off-period is determined - by a shunt capacitor 222 and a trimming resistor 223. The output 221 of the monoflop is a brief positive spike which unblocks another pilot transis-tor 224 which in turn causes power transistor 202 to conduct, thereby com-pleting the energizing circuit for coil 201. At the end of the spike the transistor 202 is again cut off, coil 201 thereupon again receiving the low voltage of +8V through diode 205.
In order substantially to prevent possible multiple responses of monoflop 220 and resulting malfunction of the switching circuit, a cur-rent-limiting network is provided. If the monoflop conducts beyond its normal time, the current in coil 201 rises toward objectionable values.
- Resistor 204, which may have a magnitude of 14.2 megohms, measures this current flow and cuts off the power transistor 202 if the latter conducts too long. Thus, a rise in the emitter potential of transistor 203 above a predetermined threshold trips an operational amplifier 225 whose output 226 is thereupon grounded, thereby lowering the base potential of pilot transis-tor 224 via a diode 227 to substantially ground potential so that transis-tor 202 is also cut off.
This method of this invention in its various aspects is not limi-~ ~ .

~09iiO5 ted to the specific embodiments of nozzles and machines for carrying out the methot of an aspect of this present invention described and illustra-ted. The ~ets of the spray nozzles adapted to be used in a machine for carrying out the method of an aspect of the present invention need not be trained into flat substrates but can be used to form patterns on bodies, hollow or otherwise of any shape. This is possible because the surface of the article to be sprayed need not be in contact with a printing screen or with a spray nozzle. The method of this invention in its various aspects is also particularly useful for the imprinting of substrates, e.g., plastic - 10 sheets, which are particularly sensitive to contact and on which successive imprinting by several screen stages would mar the color patterns already applied thereto~ The nozzles need not operate with liquid dyestuffs but could also be used for applying gaseous fluids or finely comminuted solids in a gaseous carrier to the surface of a substrate.

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Claims (15)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A method of applying patterns to a substrate comprising:
spraying a solution of a substance which creates pattern onto the substrate, said solution being sprayed directly onto said material in the form of a plurality of jets, said jets being emitted from nozzles adjustably disposed in the immediate vicinity of the substrate surface, said nozzles being opened and closed pursuant to a predetermined program.

2. The method according to claim 1 wherein said program is sensed from a matrix; and wherein the sensing commands are converted into control pulses for the nozzles.

3. A method of applying a pattern to a continuous substrate web of material having a pile surface by spraying a solution of a substance which creates a pattern thereon into the pile of the material, said solution of said substance being sprayed onto said material directly in the form of a plurality of jets which issue from a respective nozzle adjustably disposed near and substantially touching the pile surface of the material; said noz-zles being opened and closed pursuant to a preselected program.

4. A method according to claim 3 wherein said program is derived by scanning a master pattern, thereby to obtain information which is conver-ted to commands for operating said nozzles.

5. The method according to claims 1 or 3, wherein said substrate is held in a precisely defined position relative to said nozzles.

6. The method according to claims 1 or 3, wherein said substrate is located on a conveyor and is moved past said nozzles.

7. The method according to claims 1 or 3 wherein said substrate is located on a conveyor and is moved past said nozzles, wherein said sub-strate is porous and wherein suction is exerted upon said substrate or upon said conveyor in the region of said nozzles.

8. The method according to claims 1 or 3 wherein said substrate is located on a conveyor and is moved past said nozzles, wherein said con-veyor or said substrate is pressed along successive sections of its surface onto respective support rollers.

9. The method according to claims 1 or 3 wherein said substrate is located on a conveyor and is moved past said nozzles, wherein said con-veyor or said substrate is pressed along successive sections of its surface onto respective support rollers and further wherein said substrate is ten-sioned upstream of said first support roller.

10. The method according to claims 1 or 3 wherein the discharge velocity of the jets from said nozzles is at least 10 meters per second.

11. The method according to claims 1 or 3 wherein said substrate is located on a conveyor and is moved past said nozzles, wherein said noz-zles are displaced across the substrate transversely to the motion of said substrate.

12. A method according to claims 1 or 3 wherein said substrate is located on a conveyor and is moved past said nozzles, wherein said conveyor or said substrate is led in tension around part of the surface of consecu-tively disposed backing rollers.

13. A method according to claims 1 or 3 wherein said substrate is located on a conveyor and is moved past said nozzles, wherein a plurality of said nozzles are combined in an array, said array being moved as a unit across the direction of travel of said substrate and through a distance ex-ceeding the width of said substrate; said article being intermittently ad-vanced after each traverse, and said array being returned to its starting position.

14. A method according to claims 1 or 3 wherein said substrate is located on a conveyor and is moved past said nozzles, wherein a plurality of said nozzles are combined in an array, said array being moved as a unit across the direction of travel of said substrate and through a distance ex-ceeding the width of said substrate; said article being intermittently ad-vanced after each traverse, and said array being returned to its starting position, wherein said array of nozzles is mounted on rollers running on rails extending across the direction of travel of the article.

15. A method according to claims 1 or 3 wherein said substance sprayed is a printing ink or dye.