US 3374731 A
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Description (OCR text may contain errors)
March 26, 1968 w. THORNE 3,374,731
FABRIC PRINTING Filed Nov. 30, 1964 5 Sheets-Sheet 1 A 7mm/Ef March 26, 1968 w. THORNE 3,374,731
FABRIC PRINTING Filed Nov. so, 1964 5 sheets-sheet a INVENTOR.
BY WARD 7km/v5 March 26, 196s w. THORNE 3,374,731
FABRIC PRINTING Filed Nov. 30, 1964 5 Sheets-Sheet 3 27a 20C I N VENTOR. WAM@ @a/V5 Y BY l n q v March 26, 1968 W. THORNE FABRIC PRINTING 5 Sheets-Sheet 4 Filed NOV. 30, 1964 I N VEN TOR. h/A/QD @0R/VE QM s, @MAW March 26, 1968 Filed NOV. 30, 1964 W. THORNE FABRIC PRINTING Ti. E.
5 Sheets-Sheet 5 INVENTOR. W4@ Eme/v5 RMS. M
/4 TTO/P/i/Ef United States Patent O 3,374,731 FABRIC PRINTING Ward Thorne, Westport, Conn., assignor to Armstrong Cork Company, Lancaster, Pa., a corporation of Pennsylvania Filed Nov. 30, 1964, Ser. No. 414,713 2 Claims. (Cl. 101-129) This invention relates to the printing of fabrics, and more particularly relates to a method and apparatus for printing one or more ycolors in any selected. pattern upon a fabric having a pile, especially a deep-pile, in a manner such that the boundaries of each printed area are distinct and the pile is printed throughout its depth.
Techniques for printing cloth or cloth-like material are wel known, and many of these techniques are adaptable for printing fabric (e.g., carpeting) which has relatively short or stubby pile. One such technique is so-called silkscreen printing, wherein the color substance is applied to a suitably masked silk-screen and a doctor blade is employed to push the color material through the silkscreen so as to print the carpeting in contact with the underside thereof.
While such silk-screen printing is satisfactory with cloth materials and is somewhat useful with shallow pile carpeting, it is notorious in the carpet printing art that silkscreening when employed with deep-pile carpeting pro duces an indistinct or blurred edge to the pattern, or fails to penetrate throughout the depth of the pile, or both. The reason for these failures is of course inherent in the usual silk-screen process, in that a pile, and especially a deep-pile, has suicient positioning variability` at the upper portions of the pile so that during the forced passage of the doctor blade along the screens surface some local movement of the pile in contact therewithis inevitable with the result of blurring of the outline of the pattern. Also in deep-pile, the color is not or is not uniformly drawn down through the entire depth of the pile. In short then, the usual silk-screen process is unsatisfactory for the printing of deep-pile carpet, and where special attention and inspection removes the worst disadvantages thereof, it is too expensive.
Moreover, it has been found that when Wide eXpanses of carpet are to be machine silk-screened in a continuous process, the aforesaid difficulties are even further aggravated. This occurs because in wide expanses the problem of undesired shifting and moving of the deep-pile ends during printing is even worse. Thus, when only a small local area is subjected to forced passage of a doctor blade, at least the surrounding pile acts to some small extent to prevent movement of the pile in that local area. On the other hand, when as is desired in a machine process, the entire width of a wide expanse of carpet is to be printed in a continuous step-wise process, the entire deeppile is disturbed uniformly by the forced doctor blade and consequently the deleterious effects of pile looseness are increased with resulting increased detrimental printing effects.
What is needed in the art is a method and apparatus capable of printing pile fabrics, especially deep-pile carpeting, with distinct printing outlines and complete printing throughout the depth of the pile, but especially with certain other attributes. As has been suggested, these other attributes desirably include the ability to perform such printing in a continuous or a continuous step-Wise process, such as for example where a certain length of carpet is printed while stationary and thenV automaticallyy moved forward while a subsequent segment of carpet is printed while stationary. Another very desirable attribute would be the ability to print an entire width of carpet in such a continuous or continuous step-wise operation,
3,374,731 Patented Mar. 26, 1968 so that the carpet need be moved continuously in only one direction.
The basic desire to have an apparatus and process for printing distinct and deeply dyed patterns on deep-pile carpet is of course qualitative, i.e., it is a long standing problem in the art to attain this by any reasonable ma- Chine technique. The desire to do so by a continuous process, and particularly by a continuous process wherein the entire width of carpet is covered in each printed segment, is more quantitative in nature in that it relates very particularly to the requisite process economy which is sought in this art. Nevertheless a single solution to both aspects of the problem has long been sought, so that deep-pile carpeting might be offered in the trade with printed patterns comparable to those attainable with fabrics by the standard silk-screen process and Without undue added printing costs.
It is accordingly a principal object of the present invention to provide a method and apparatus for the printing of pile fabric so that the outline of each printed area is distinct and unblurred and so that the printed pile is dyed throughout its depth.
Another object of the invention is to provide such a method and apparatus wherein deep-pile carpeting may be machine printed in a continuous process.
Another object of the invention is to provide such a method and apparatus wherein broad widths of deep-pile carpeting may be machine printed in a continuous process.
Another object of the invention is to provide such a method and apparatus wherein superior printing is combined with superior economy in the printing of deep-pile carpeting.
These and further objects, features, and advantages of the invention will be more fully appreciated in the light of the detailed description of one illustrative embodiment of the invention contained hereinbelow. The invention is described with reference to the drawings in which like reference characters denote like parts in all views thereof, and in which:
FIGURE 1 is a top view of an apparatus according to the invention capable of continuously printing a wide swath of deep-pile carpeting in step-wise fashion,
FIGURE 2 is a side View of the apparatus shown in FIGURE 1,
FIGURE 3 is an enlarged partially sectioned end View of a portion of the apparatus shown in FIGURES l and 2.
FIGURE 4 is an enlarged top view of a detail of a portion of the apparatus shown in FIGURE 3.
FIGURE 5 is a side View of the detail shown in FIGURE 4,
FIGURE 6 is a process diagram detailing the steps practiced according to the invention, and
FIGURE 7 is a detail of a portion of the apparatus shown in FIGURES l and 2.
Briefly, the present invention provides an apparatus and method adapted to attain the aforesaid objectives. A very tine screen is disposed over the fabric in proximity to the surface of the pile, and a thick layer of liquid coloring material is applied on the face of the screen opposite to the fabric in the desired pattern. Attainment of the desired pattern can be effected by masking certain areas of the screen by the normal silk-screen blocking techniques, or by any other suitable techniques. It is important to the practice of the invention that the liquid coloring material which is applied to the screen is incapable of passing through the apertures of the screen under its own weight alone. Further means are provided for applying a transient gas pressure increase upon said layer of liquid coloring material so as to drive a multiplicity of very fine jets of coloring material through saidscreen to and down along the depth of said pile. The
3 Y combination of a very fine screen with a transient pressure driven layer of coloring material supported thereby, provides, by means of the aforesaid multiplicity of very fine jets of coloring material, a very clean-cut and direct application of coloring material to the underlying7 pile so that coloring of the pile throughout its depth is attained for the first time in combination with the very clean-cut segregation of colored and uncolored pile which constitutes the desired sharp borders to the colored pile area.
Referring now to the figures, and particularly to FIG- URES l and 2, a conveyor arrangement indicated generally at 10 conducts the carpeting or other deep-pile fabric 11 from a source 12, indicated as a supply roll on axle 12a in the figures, to an egress area indicated generally at 13, where the fabric 11 may be taken up for further processing such as drying, cutting, or the like where desired. Conveyor assembly 10 constitutes a general framework 14 which provides a fiat upper platform surface 15 suitable for the traverse of fabric 11 from source 12 to egress area 13. A series of propeller rollers 15a, 15b, 15C, and 15d, are provided at spaced locations along the surface 15. A plurality of idler rollers 16a, 16b, 16C, 16d, 16e, 16], 16g, 16h, are also provided along the general framework 14.
An endless drive chain 17 is threaded among the various propeller rollers and idler rollers and drive sprocket 17a on drive shaft 17b. The chain 17 is threaded among these elements in a manner such that the chain comes in Contact with a 2-3" lateral burlap edging 11a of the fabric lying along platform 15 of general framework 14 at propeller roller 15a and at propeller roller 15d, forming the entrance and egress of the fabric 11 relative to platform 15, and also at and between propeller rollers 15b and 15C. As is shown in FIGURE 7, chain 17 comprises a series of links 17a, an occasional link 17b of which contains a spike 17c. In practice the spikecarrying links are spaced several inches apart 'on chain 17, e.g., six inches apart. A motor means (not shown) may be employed to drive sprocket 17a. The spikes 17C on chain 17 are thereby driven at propeller rollers 15a, 15b, 15C, 15d, into contact with fabric 11' and fabric 11 is thereby smoothly propelled along platform surface 1S from one end thereof to the other. It is generally preferable not to drive supply roller 12a since the supply rate depends on the amount of fabric 11 left thereon. By driving only sprocket 17a, the idling source roller 12a automatically supplies fabric 11 at the proper rate.
Arranged along platform 15 is a plurality of printing stations, two of which are shown generally at 18 and 19 in the figures. As will appear more clearly hereinbelow, at least one printing station must be employed, and the number of printing stations in excess of one that are employed will depend upon the complexity of the pattern which is to be printed as regards the number of separate colors. For purposes of description, two stations 18 and 19 are shown, and this arrangement will be most advantageous where two colors, in addition of course to the background color (if any) of the fabric 11 as it enters upon platform 15, are to be printed. The stations 18, 19, are identical in terms of their operation, although when they are employed to print different portions of a pattern they will of course include suitable modifications such as differences in masking or blocking necessary to accomplish that end.
Understanding of the construction and operation of stations 18, 19, will be expedited by recourse to FIG- URES 3, 4, and 5 in conjunction with FIGURES 1 and 2. In general a station 18 or 19 will constitute a relatively gas tight chamber enclosure 20, which enclosure constitutes essentially a box having an incompletely closed bottom face 20c adapted to rest upon platform 15. The entire chamber 20 and the elements carried thereby, is connected to main overhead rail 42 by hydraulic cylinders 43. Main overhead rail 42 is carried by pillars 44 which form part of main frame 10, and thus chamber 20 may be raised and lowered relative to platform 15 @harnber 20 communicates at its upper face 20a withga plurality of pressuring cylinders 22 arranged transversely of the direction of travel of fabric 11 on platform 15. In the drawings three cylinders 22 are shown, but the choice of the number of cylinders is a matter of design. In practice one large cylinder encompassing the width of fabric 11 may be employed, or a plurality of cylinders as shown may be employed. The cylinders 22 are secured to chamber 20 by wing-bolts 22a for a purpose to be hereafter explained.
Each cylinder Y22 communicates with the interior of pressure chamber 20 via alarge mouthed orifice 20h therebetween. Each cylinder 22 carries a piston 23 therein, which piston includes a check-valve 23a and which piston is smoothly operable upward and downward within the bore of the cylinder 22. The piston 23 is driven by a rod 24 which terminates in an actuating piston 2S carried in a double acting actuating cylinder 26. The rod 24 with pistons 23 and 25 is thereby capable of motion upwardly and downwardly within the cylinders 22 and 26 within restraints. Cylinders 26 are fixed relative to chamber 20 by means of overhead rail 40 which is supported on chamber 20 by columns 41. Into double-acting cylinder 26 is admissible by valving means (not shown) a propelling uid. which may be either liquid or gaseous and which is employed to drive piston 25 and thereby pistou 23, suddenly downwardly and return it upwardly. The sudden descent of piston 25 causes the equally sudden descent of piston 23 with the result that a transient pressure change is communicated to the interior of enclosure 20.
Fabric 11 is carried upon platform 15 at the printing station and within opening 20d in bottom face 20c of chamber 20, as is best shown in FIGURE 3. A very fine screen 27 is carried across bottom face 20c, and across opening 20d therein in close proximity to the pile of fabric 11. Masking of the portion of screen 27 crossing opening 20d may be accomplished by any of the wellknown techniques. For example, the areas 27a may be blocked out by opaque areas in the screen 27 itself. Disposed normally to one side of platform 15 is a doctor blade assembly 28 carrying a pair of doctor blades 29 and 30. As is best shown in FIGURES 3, 4, and 5, doctor blade assembly 28 comprises a pair of dollies 28a each supported by four flanged dolly wheels 30 and adapted to traverse a monorail 31 mounted along a transverse wall 20c and 20d respectively of enclosure 20. As is shown in FIGURE 3, each dolly is held at any given position along rail 31 by a chain 32 which rides aroundra plurality of idler wheels 33. By manipulation of the chains 32 of the dollies 28a, the dollies 28a may be made to traverse the entire width of rail 31 in either direction together, thereby traversing the entire width of fabric 11 contained thereinbelow.
As is best shown in FIGURES 4 and 5, doctor blades 29 and 30 traverse essentially the entire length of enclosure 20 when dollies 28a are caused to ride from one end of rail 31 to the other. Thus a combined sweep of doctor blades 29 and 30 covers essentially the entire area beneath enclosure 20. Between doctor blades 29 and 30, as is best shown in FIGURE 3, is disposed a quantity of coloring material of a liquid or semi-liquid consistency indicated at 34, to be more fully described hereiubelow. During a complete transverse of doctor blades 29 and 30, coloring material 34 is pushed, in the space between blades 29 and 30, from one side of enclosure 20 to the other side. The amount of material that is deposited on the surface traversed by the doctor blades is determined by the vertical spacing of the edge of the doctor blades therefrom, by means to be more fully described hereinafter. Essentially, in the present invention a relatively thick deposit of coloring material 34 will be spread during the sweep of the doctor blades, and particularly will be spread upon the portion of Very line screen 27 which lies over fabric 11.
It is a characteristic of the combination of very fine screen 27 and coloring material 34 that no coloring material 34 passes downward through screen 27 merely because of the weight of coloring material 34. The precise relationship of screen 27 and coloring material 34 which accomplishes this end will be described more fully hereinbeloW. It is essential for present understanding however', that it be noted that the doctor blades 29 and 30 are spaced somewhat upwardly from the surface of screen 27 so as not to place any downward pressure behind coloring material 34 as it is deposited on screen 27 during the sweep of the blades thereacross, and that the coloring material 34 itself does not thereafter permeate downwardly through the screen 27 under its own weight. For this reason the present doctor blades 29 and 30 do not perform the same function as doctor blades employed in silk-screen conventional fabric printing, wherein the doctor blade squeezes the color through the screen.
When it is desired to increase or decrease the thickness of the generally thick layer of coloring material 34 which is deposited across screen 27 by doctor blades 29 and 30, the dolly adjusting apparatus best shown in FIGURE 5 is restored to. Since dolly 28 rides upon fixed rail 31, the height of dolly 28a above platform surface 1S or above screen 27 is xed. However blades 29 and 30 are attached to dollies 28a by means of wing members 35 at each end of each doctor blade, which wing members are slotted for vertical sliding cooperation with a shoulder assembly 36 of each dolly 23a, Shoulder assembly 36 includes a screw member 37 which cooperates with a threaded portion of wing-member 35 on the doctor blade, to raise and lower the doctor blade in -accordance with the appropriate turning of screw 37 in one direction or the other. A pointer 35a is provided on wing member 35 and an index 36a is provided on a portion of shoulder assembly 36 so that relative elevation and depression of the doctor blade relative to the dolly assembly 28a may be accurately set. Thus by the appropriate turning of the two screws 37 associated with each of doctor blades 29 and 30, the doctor blades can be set to an equal and precise spacing above screen 27, thereby precisely adjusting the thickness of the layer of coloring material 34 which is deposited upon the screen 27 by the doctor blades in their traverse.
The necessary relationship between the screen 27 and the coloring material 34 will now be described. It is necessary in the practice of the present invention that the screen 27 have very tine apertures so as to produce very fine jets of coloring under the influence of the aforesaid transient pressure increase, for purposes to be described hereinafter. In addition, it has been found that this same very fine screen configuration enables attainment of another necessary condition with the invention, namely that the coloring material 34 shall remain suspended upon screen 27, without passing through the apertures thereof, against the inuence of the coloring materials weight.
Thus with a very tine screen 27 the consistency of coloring material 34 may be adjusted until a balance is achieved between retention of the coloring layer on screen 27 under the weight of coloring material alone, and jetting-through the apertures of screen 27 under the influence of the said transient pressure increase. While conventional silk-screening processes employ screens having in the order of 60-100 mesh, according to the present invention screen 27 must be 300 mesh and finer (higher mesh).
It has been found that a screen of this size which works very well with the present invention may be fabricated from monofilament nylon warp and woof threads. While other types of screen of the size described may be employed, it is preferable that the threads comprising the screen be of a relatively smooth outline so as to hinder clogging of the screen apertures. It is therefore preferable with the present invention to employ screens constructed from nylon and other synthetic or natural Ipolymeric threads, particularly monotilament threads, so as to increase the non-clogging service life thereof. Screens having a mesh in the order of 300 correspond to apertures therein of the order of 0.0015 diameter.
As previously mentioned the essential relationship between screen 27 and coloring material 34 is that the coloring material should be supported upon the screen without passing through under the weight of the coloring material itself, while under the influence of a suddenly applied pressure differential the coloring material 34 should be capable of being rapidly exuded through the pores of screen 27 as a plurality of tine jets. This can be accomplished by increasing the thickness of coloring material 34 to a point suicient to resist gravity flow through screen 27. Commercially available gums may be used as thickeners, but in general gums are not preferred. An excellent way to thicken coloring material 34 until it will rest upon screen 27 without permeation therethrough under the intiuence of gravity is to add thereto a mixture of mineral spirits in water containing an emulsifying agent, for example the material Varsol (manufactured 4by the Standard Oil Company of New Jersey) may be added to an aqueous dye solution conventional in the deep-pile fabric printing arts until the desired consistency is obtained. In general the consistency required for use with the present invention is approximately two to three times the 4thick-y ness of that employed in silk-screen textile printing operations.
It is anticipated that other methods of supporting a layer of coloring material 34 upon fine screen 27 may be employed. For example fine screen 27 may be coated with a hydrophobic agent, and under this condition a relatively thinner coloring material 34 (compared to that just described) may be supported against its gravity force upon the surface of screen 27. Other means for supporting a layer of coloring material 34 upon screen 27 against gravity force may 4be substituted, but thickening of coloring material 34 to attain that end is the -preferred technique. Any technique which is employed is satisfactory if it prevents passage of coloring material 34 through screen 27 under its own Weight, but allows the rapid jet-like passage therethrough under a suddenly applied pressure differential, which differential is described hereinbelow.
The layer of coloring material 34 which is deposited upon very ne screen 27 is adjusted by means of screws 37 as already described. The actual thickness of the layer which is applied =will be chosen in accordance with the nature of the fabric 11 which is to be printed, once the coloring material 34 has itself been standardized with regard to screen 27 and the profile of pressure differential application hereinafter described. That is to say, once empirical experience has been gained with the particular combination of parts including coloring material 34 and a correlated screen 27, the apparatus may be employed with Various types of fabric 11 ranging from fabric without a pile through so-called needle-punch carpet up to and including deep-pile polyester filament carpeting.
In general, of course, the deeper the pile on fabric 11 the thicker will be the layer of coloring material 34 which is predetermined by means of screws 37- For example with a fabric 11 of little or no pile, a 1/16" or less layer of coloring material 34 may be necessary, while with deeppile fabric a 1A layer or even more of coloring material 34 may be required. The actual precise adjustment of the layer that is required will be empirically determined -by the amount needed to penetrate essentially to the base of the pile or nap of the fabric 11 in question. Actually during the actual printing the color need not extend to the absolute bottom of the pile since a small fraction of the depth of coloring may be added during a subsequent standard steaming operation discussed hereinbelow. Of course it is a feature of the invention that during printing itself penetration throughout the entire depth of the pile may be practiced, but it is also a feature that the precise adjustment of the depth of printing which is possible with the invention allows a certain degree of economy with coloring material 34 by taking advantage of the fact that the subsequent steaming operation bleeds the color a little deeper than is originally printed.
The transient pressure differential which is applied at openings 201; is essential in the practice of the invention. That is to say, the jetting of coloring material 34 through screen 27 may be viewed as an impact phenomena, and it has been found that a stream of air or gas applied to the upper surface of the coloring material does not produce satisfactory results. Apparently the clean-cut boundary between printed and unprinted pile or nap can be attained only when a sudden and momentary and very fine jetting of coloring material 34 is practiced. When a suddenly applied but thereafter continuous stream of air or gas is applied, blurring of the edges of the pattern often occurs, and it is speculated that this blurring is a result of dripping through or other forms of permeation of screen 27 by coloring material 34 other than jettingthrough, caused by a continuous pressure differential above the layer of coloring material 34 such as is produced by a continuous stream.
While it is possible to valve a source of air or gas supply such that a transient pressure differential is applied, it is preferred to employ the piston 23 arrangement previously described, because primarily of the fine control which is attainable therewith. One of the main advantages of the present invention is the very fine control of coloring material V34 and screen 27 that is possible, with the resultant finely adjustable printing characteristics. It is consequently preferable to employ a finely controlled transient pressure differential mechanism such as illustrated in the drawings in order to give this advantage full effect. Since the volume of cylinders 22 is but a fraction of the volume of enclosure 20, the volume of air or gas which passes into enclosure 20 from cylinders 22 under the actions of pistons 23 is not such as to cause what could be described as significant ow of gas through enclosure and screen 27. Indeed, as has just been explained, a true continuous fiow therethrough is not desirable. Rather the pistons 23, when actuated by pistons 25, produce a rapid elevation in pressure within enclosure 20 which is sustained for the duration of the descent of piston 23 and which terminates immediately upon the bottoming of pistons 23 within cylinders 22. However, there is of course some flow during the transient pressure differential, and accordingly the enclosure. 20 is arranged to be relatively air-tight so that the effect of the transient elevated pressure, and the ow, is to the unmasked portions of screenr27 with the layer of coloring material thereon. This momentary flow escapes throughout the pile of fabric 11 thereunder.
In general the order of magnitude of time of this pressure differential is approximately a fraction to one or two seconds. The shorter periods are preferred. It is during this relatively short period of time that the coloring material 34 is forced through screen 27 in a plurality of extremely fine jets, and at the expiration of this period the jetting action is instantaneously stopped. It has been found that'with this type of clean-cut jetting, the screen 27 reasserts its ability to hold the remaining (if any) layer of coloring material 34 against gravity forces so thatno dripping through or other permeation of screen 27 occurs which could blur the outline of the printedY Y pattern. In effect then, screen 27 acts as a valve for the coloring material except under the condition of a certain pressure differential, and since the pressure differential is vapplied essentially as a transient, the coloring material 34 only passes through screen 27 in the desired jetting action and not by any other and deleterious way, Veither before or after the transient. This results directly in the highly desirable deep dyed yet clear outline pattern attained with the means of the lpresent invention.
-In operation, the illustrated equipment functions as follows. A reel 12 of fabric 11 (having an edging 11a) is applied to roller 12a and a loose end of the fabric 11 is threaded around propeller roller 15a (where the spikes 17e of chain 17 engage and advance it), and under the adjacent printing station assembly 19. In order to avoid wastage, it is advantageous to hand tend the first few feet of fabric 11 through station 19 and subsequently through station 18. An obvious alternative is to thread fabric 11 through both stations 19 and 18 before any printing has begun, Ibut as aforesaid, thisl does waste a few feet of fabric. In any event when the fabric is secured under the stations, station 19 will be adapted to print a portion of the final fabric pattern, and station 18 will be adapted to print another portion of that final pattern.l
While two stations are shown, of course further stations may be provided where greater than two colors are to be printed upon fabric 11.
Each of stations 18 and 19 will previously have been supplied with an appropriate coloring material 34, and a very fine screen 27 (masked at 27a) of appropriate mesh to cooperate with the particular coloring material 34 in a manner as already described. Sprocket 17a, and consequently .each of propeller rollers 15a, 15b, 15e,
' 15d, via chain 17, will be intermittently Vdriven by motor means (not shown) of conventional design, so that a segment of fabric 11 is driven under station 19 and another further advanced segment is driven under station 18, and then the fabric 11 is stopped while printing occurs. During periods of advance of fabric 11, the whole chamber 20 is lifted free of fabric 11 by cylinders 43. This operation is of course repeated continuously so` that a continuous step-wise advance of fabric 11 along platform 15 occurs, and fabric 11 is printed in a series of contiguous areas coextensive with the printing area under each station. While it is preferable to drive the fabric 11 at edging 11a, it is also possible to cause chain. 17 to drive the main body of fabric 11 directly.
Each time fabric 11 is stopped the chamber 20 is lowered to the position shown in FIGURE 3, and doctor blades 29 and 39 are' caused to traverse screen 27 leaving a relatively thick layer of coloring material 34 thereon, both by motor means (not shown) in response to the stopping of fabric 11, as for example by a relay (not Y shown) which closes upon such stoppage. It is of course also possible to apply coloring material 3-4 between periods of stoppage of fabric 11 rather than during the periods of stoppage, but this is not preferred( Y When the fabric 11 has stopped for printing, the pistons 25 are suddenly energized downwardly by a pressurized uid which is introduced at 26a. This energization is preferably in response to the termination of the traverse of doctor lblades 28 and 29. Energization means other than piston 25 for driving piston 23 may of course be employed. An example alternative is driving rod 24 with a solenoid, and another is driving it with a cam. Others will occur to those skilled in the art. As has previously been mentioned the requisite transient pressure differential may itself be supplied by means other than piston 23 in cylinderr22, but the illustrated means is preferred.
When piston 23 is actuated downwardly byY the energization of piston' 25, the check-valve 23a in piston 23 closes, and the lise in pressure in chamber 20 caused by -the descent of piston 23 causes the layer of coloring material 34 to be driven through screen 27 in a multiplicity of fine jets and into fabric 11. The'period of dwell of fabric -1-1 is then terminated and the whole chamber 20 is lifted by cylinders 43 again, and. the vfabric is driven adistance equal to the distance printed under one of stations 18 or 19, whereupon the fabric 11 is once again stopped andranother printing sequence is made. Each time a printing sequence is ended, pistons 23 are raised again,- and because check-valve 23a opens during that raising, no air ow enters chamber 20 from lower opening 20c during that raising.
It will be appreciated that at each stop in the passage of fabric 11 along platform 15 printing is accomplished at both stations 18 and 19. It is clearly advantageous for stations 18 and 19 to cover equal printing areas, and it is also advantageous for the distance between the extremities of printing stations 18 and 19 along platform 15 to be an integral multiple of the length of the printing area of at least printing station 19 (and preferably, Where the printing stations are equal, of both printing stations 18 and 19). It is possible to so sequence the stops such that other arrangements may be accommodated, but the arrangement just described is the simplest and most direct method. Under that arrangement, and with the proportions shown in the gures, an area just printed by station 19 will advance 'and stop twice while printing station 19 is printing two further segments, before t-he first mentioned segment, on its third advance, enters under printing station 18 and is printed. Whenever coloring material 34 needs replenishing, the adjacent cylinder 22 may be freed by releasing bolts 22a, and swung out of the Way, to give access through orifices 20b to the doctor blades 29, 30.
As may be best seen in FIGURE 1, the lirst portion 11x of the final pattern has Ibeen applied to the material which has left printing station 19 and is approaching printing station 18, while both the portions of the pattern 11x and 11y are present in the fabric which is shown leaving printing station 18. Of course, more complex patterns may be applied, by employing a greater number of stations with a greater number of colors. Also superimposition of colors may be practiced. The illustrated fabric 11 has been chosen for simplicity to clearly illustrate the principles. After leaving platform fabric 11 is treated further in a conventional manner.
Referring particularly to FIGURE 6 a method according to the present invention, and which is implemented by the illustrative 'apparatus shown in the figures, comprises presenting an appropriately blocked very tine screen 27 of at least 300 mesh across a portion of the fabric which is to be printed, applying a thick layer of liquid coloring material on the face of the screen opposite to the fabric so that the unblocked area is covered with said coloring material to a predetermined thickness, the relationship between said liquid coloring material and said screen being such that the liquid coloring material does not run through the screen under its own weight, and while maintaining the screen enclosed against appreciable escape of air except through said unblocked area, directing a transient air pressure differential against the upper surface of said layer of coloring material to drive the coloring material through the screen and into the pile of the fabric.
After the process of printing which is attainable with the illustrative apparatus shown in the figures has been completed, the fabric 11 after egress from propeller roller 15d is supplied to a further station (not shown) whereat it is subjected to further and standard treatment known to the art. This further treatment will typically include steamin-g of the fabric 11 followed by washing in soap and water, rinsing in water, and then drying.
What has been described is a method for printing fabrics having a nap or pile, particularly a deep-pile, and an example apparatus for accomplishing that process. The essential problem in the art of printing deep-pile fabrics particularly, has been that the coloring materials either did not penetrate deep enough into the pile or did produce an indistinct or blurred margin to the printed pattern, or both. What has now been discovered is that a relatively thick layer (e.g., over 3/50) of coloring material can be arranged (by one of the techniques discussed, or by other techniques, and preferably by increasing the thickness of consistency thereof) so that a very line screen, i.e., over 300 mesh, will support the coloring material layer against gravity forces, yet will not only allow the coloring material through under an applied pressure differential, but will produce a multiplicity of very line jets which are capable both of reaching deeply into the pile and of producing ya distinct border to the printed pattern. It should be noted that the reltionship between the screen and the coloring material is such that the coloring material is retained both before and after the transient pressure differential is applied. Thus, in effect, the screen acts as a valve which only allows coloring material through under the condition of a pressure differential, and consequently color is either jetting-through or is not coming through at all. This results in the deep coloring produced by jetting-through, and also in lack of oozing before or after the jettingthrough so that the distinct 'borders produced by the jets are not blurred.
The present process thus provides for the first time a continuous step-wise machine printing process for material having a nap or pile, and particularly for deep-pile material, which produces deep coloring of the pile with distinct pattern borders. The advantages of machine and continuous process techniques are now available with this class of fabrics for the iirst time in combination with the desired characteristics of printing itself.
The invention has been described with reference to a particular and preferred embodiment thereof, but it should be clearly understood that the embodiment shown in the figures is illustrative of the inventive principles and is not limiting. Various changes, some of which have been pointed out herein, may be made in the form and arrangement of parts Without departing from the spirit and scope of the invention itself.
What is claimed is:
1. A method of printing a pattern on a pile fabric comprising disposing over the fabric in proximity to the surface of the pile a screen at least as fine as 300 mesh having blocking at portions thereof so as to form said pattern at the unblocked parts; selecting a liquid coloring material of sufficient viscosity to be retained against gravity on said screen and to maintain a mechanically graded level; applying said liquid coloring material in a relatively thick layer of liquid coloring material on the face of the screen opposite to the fabric to a controlled substantially uniform thickness of at least M30 inch by mechanical grading; directing a transient gas pressure increase against the free surface of said liquid coloring layer suiicient to cause passage of all the coloring material overlying said unblocked screen portions therethrough into said pile fabric.
2. A method according to claim 1 wherein said pile fabric comprises carpeting; wherein said applying step comprises drawing a doctor blade across said fabric, spaced upwardly therefrom to said substantially uniform controlled thickness distance, with said coloring material carried before said doctor blade; and wherein said directing a transient gas pressure increase lasts for a duration of not more than about one second.
References Cited UNITED STATES PATENTS 1,323,620 12/1919 Deleeuw 101-129 X 1,821,302 9/1931 Gomer.
40,857 12/1863 IRogers 101--114 1,786,347 12/1930 Kennedy lOl-114 2,237,179 4/1941 Gromm lOl-115 X `2,292,602 8/ 1942 Biondi 101-116 3,129,442 4/ 1964 Leckie 101--129 X 3,172,358 3/1965 Weiss lOl-115 X FOREIGN PATENTS 1,148,961 7/ 1957 France. '1,175,156 1l/1958 France. 591,691 4/ 1959 Italy.
OTHER REFERENCES Kosloff: Photographic Screen Process Printing, The Signs of the Times Publishing Co., 1962, p. 19.
DAVID KLEIN, Primary Examiner.