Abstract:
An apparatus is provided which applies and cures a coating of viscous ink to a moving strand material. This apparatus includes an ink applicator module which comprises a series of rotatable rollers which receive and apply the ink to the moving strand. This apparatus allows substantial quantities of glass fiber waveguide strand material to thus be coated with a UV curable ink in a relatively short period of time so that they may be color coded to facilitate handling and installation.

Description:
FIELD OF THE INVENTION 
     This invention relates to apparatus for applying and curing a coating of a viscous ink to a moving strand material. More particularly, this invention is directed to such apparatus for applying such a coating to glass fiber waveguides and the coating being an ultraviolet curable ink. 
     BACKGROUND OF THE INVENTION 
     The use of optical glass fiber waveguides as a desired means for transmitting data has continued to grow in popularity. Fiber optic linkages have a very high information carrying capacity for their relatively small cross-sectional size, particularly in comparison to metal conductor wires. 
     Typical data transmission systems and lines employ great numbers of these glass fiber waveguides bundled into relatively small spaces. But since they are virtually identical in appearance, it is practically impossible to properly interconnect and splice these waveguides together without some assistance in their identification. 
     A desired manner of such identification is disclosed in commonly owned co-pending U.S. patent application Ser. No. 582,091 filed Feb. 21, 1984, which deals with providing color coded optical fiber waveguides. As discussed therein, the waveguides are color coded such as in accordance with the standard telecommunication code as metal conductor wires typically are so as to provide ready and sure identification. This color coding is accomplished by applying a relatively thin and uniform coating of colored ink on the waveguides. The ink is preferably a viscous ultraviolet curable ink which is capable of being applied in very precise amounts. 
     Conventional apparatus, however, is not capable of applying the ink in a desired manner. It has been therefore necessary to develop apparatus that can accomplish this. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention there is accordingly provided apparatus for applying and curing a coating of a curable viscous ink to a moving strand material, which apparatus comprises strand supply and takeup spools, a supply of curable viscous ink, ink applicator apparatus and means for curing the coating of the ink, with the ink application and curing taking place continuously while the strand is moving from the supply spool to the takeup spool. The coating of viscous ink can be UV curable in which case there can be provided a source of ultraviolet radiation as the means for curing the ink. 
     The ink applicator apparatus thereof comprises a series of rotatable rollers successively arranged in driving engagement. When rotated, these rollers successively transfer the ink from an ink receiving nip defined by first adjacent rollers along intermediate rollers and finally to an applicator roller at the applicator end of the series. The applicator roller is adapted for applying the ink to the moving strand in the desired fashion so that as the ink is applied by the applicator roller it is removed by and applied to the strand. 
     The series of rollers can include an ink positioning roller which has a peripheral surface formed of a resilient elastomeric material and which has a circumferentially extending concavity formed therein. This positioning roller effects a centering of the ink deposited on it and on successive rollers for more precise ink placement. 
     The moving strand is directed substantially tangentially across the surface of the applicator roller and a substantially uniform thickness coating of ink is thereby applied to the strand. In connection with this, a weighted roller can be included in association with the applicator roller and in peripheral contact therewith to maintain a predetermined contact pressure of the strand as it contacts the applicator roller and assists in ink application. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further and more specific features and advantages of the invention will become more apparent when taken in connection with the accompanying drawings, in which 
     FIG. 1 is a perspective view of a machine of the invention having a plurality of operating positions; 
     FIG. 2 is a side elevational schematic view of one of the operating positions of the machine of FIG. 1; 
     FIG. 3 is a fragmentary perspective view of an applicator module of the invention; 
     FIG. 4 is a side cross-sectional view of the applicator module; 
     FIG. 5 is a fragmentary detailed perspective view as viewed from the arrow 5 of FIG. 4; 
     FIG. 6 is a fragmentary perspective view with details exaggerated for illustration of the juncture designated as 6 of FIG. 4; 
     FIG. 7 is a fragmentary horizontal cross section taken along the lines 7--7 of FIG. 6; 
     FIG. 8 is a fragmentary horizontal cross section taken along the lines 8--8 of FIG. 6; 
     FIG. 9 is a fragmentary horizontal cross section taken along the lines 9--9 of FIG. 6; and 
     FIG. 10 is a fragmentary perspective view as viewed from the arrow 10 of FIG. 4. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     While the present invention will be described more fully hereinafter with reference to the accompanying drawings, in which particular embodiments of the present invention are shown, it is to be understood at the outset of the description which follows that persons of skill in the appropriate arts may modify the invention here described while still achieving the favorable results of this invention. Accordingly, the description which follows is to be understood as being a broad, teaching disclosure directed to pesons of skill in the appropriate arts, and not as limiting upon the present invention. 
     Referring now more specifically to the drawings, FIG. 1 illustrates a machine 10 of the invention having a plurality of operating positions. In the machine shown, there are eight such operating positions employed. Each such position is contained within and supported by machine frame 12 and includes a supply spool 13 of strand material 14 carried by one end of frame 12 and a takeup spool 15 for strand material carried by the other end of frame 12. For each strand 14, a respective predetermined individual strand pathway 16 extends along said machine frame 12 between said supply spool 13 and said takeup spool 15 and determines the path upon which strand 14 is moved. Desirably both said supply spool 13 and said takeup spool 15 have drive motors associated therewith (shown schematically in FIG. 2 as 13a and 15a respectively) for moving said strand 14 at a controlled rate of speed and with a controlled amount of tension. 
     For each strand, an ink applicator apparatus or module 20 is provided along the strand pathway 16 and is associated with a respective individual supply 30 of curable viscous ink carried by frame 12 and adapted for coloring the moving strand 14. Each supply 30 includes an ink pump P (FIG. 2) and a curable viscous ink 31 of desired color. After ink applicator apparatus 20 applies a coating of curable viscous ink 31 to strand 14, strand 14 is passed through passageway 40 where it is subjected to means for curing the coating of ink on strand 14. This is positioned along strand pathway 16 between ink applicator 20 and takeup spool 15. 
     Referring now to FIGS. 3 through 10 and more specifically to ink applicator module 20, said module apparatus further comprises a series of rotatable rollers successively arranged in driving engagement with peripheral surfaces of adjacent rollers in contact with one another. Said series of rollers includes a first roller 21 at one end of the series having its peripheral surface positioned in engagement with a second roller 22 of the series to define an ink receiving nip 23. Said series of rollers also includes an applicator roller 24 at the end of the series opposite that of said first roller 21. Applicator roller 24 is adapted for applying the desired coating of ink 31 to the strand 14. 
     An ink injector 32 in the form of a hollow tube directs the selected ink to the ink receiving nip 23. Means is provided for rotating the rollers of the series so that ink 31 is successively transferred from the ink receiving nip 23 along the peripheral surfaces of each of the rollers in the series and to the applicator roller 24. The means for rotating the rollers, as shown in FIG. 3, can comprise drive means in the form of a drive roller 25 driven by a drive motor (not shown). Drive roller 25 is operatively connected to and directly drives applicator roller 24. The remaining rollers of the series are mounted for free rotation and are thus driven by the movement of applicator roller 24. 
     As shown in FIGS. 3 and 4, an ink positioning roller 26 is mounted in peripheral engagement with second roller 22 for transferring the ink 31 from the peripheral surface of the second roller 22 to the peripheral surface 26a of the ink positioning roller 26. The peripheral surface 26a of the ink positioning roller 26 is desirably formed of a resilient elastomeric material, such as rubber or plastic, and as shown in FIGS. 6 and 7 has a circumferentially extending concavity formed therein so as to be desirably v-shaped in cross section. And as shown in slightly exaggerated fashion in FIG. 6 (as well as in FIGS. 7 through 9), in operation the peripheral surface 26a of the ink positioning roller 26 tightly engages the peripheral surface of the second roller 22 so that upon rotation of the ink positioning roller 26, this concavity is flattened as it passes through the nip. This serves to work and flatten out the viscous ink 31 and spread it evenly across the peripheral surface 26a. Then as the ink positioning roller 26 further rotates, its peripheral surface 26a returns to its concave configuration upon leaving the nip and the ensuing suction action between the peripheral surface 26a and the ink 31 causes the ink 31 to move to the apex of the v-shape of surface 26a. Ink 31 is thus deposited on the peripheral surface 26a of the ink positioning roller 26 and centered in the circumferentially extending concavity. Ink 31 is then centrally positioned as desired on the positioning roller 26 and on succeeding rolls and on strand 14. 
     The series of rollers of the applicator module 20 also includes an ink transfer roller 27 mounted between the ink positioning roller 26 and the applicator roller 24. This transfer roller 27 cooperates with the applicator roller 24 for transferring the centered ink 31 from the ink positioning roller 26 to the applicator roller 24. 
     In the series of roller the peripheral surfaces of each roller is desirably formed of a different material from that of each adjoining roller (for example, rubber to metal to rubber to metal to rubber) to facilitate the transfer ink 31 from one adjacent roller to the next. Each roller also has an external diameter different from that of any other roller in the series to eliminate the possibility of an undesirably repeating pattern of ink being formed. Furthermore, the rollers in the series are desirably mounted about parallel axes, with first roller 21 being mounted on an eccentric shaft to impart a variable contact pressure on the respective rollers in the series. 
     At the application end of the series of rollers is applicator roller 24. In association therewith there is provided means for directing the moving strand 14 tangentially across the peripheral surface 24a of the applicator roller 24 so as to apply a substantially uniform coating of ink 31. There is included a weighted roller 28 mounted on an idler arm 29 which cooperates with and is in peripheral contact with the applicator roller 24. The weighted roller 28 is thus mounted for passage of the moving strand 14 between it and the applicator roller 24, and it maintains a predetermined contact pressure on the strand 14 as it contacts the applicator roller 24. 
     Applicator roller 24 preferably has a peripheral surface 24a formed of a resilient elastomeric material in the area in which strand 14 contacts the surface of applicator roller 24. This is to assure intimate contact of the strand 14 with the peripheral surface 24a of the applicator roller and the ink 31 carried thereby so that the coating of ink 31 being applied extends to at least 180° of the circumference of strand 14. The coating of ink 31 can be applied continuously along the length of strand 14 or discontinuously so as to be patterned in bands by using an applicator roller with a predetermined surface. 
     Optionally, and as illustrated in FIG. 10, the peripheral surface 24a of the applicator roller may be provided with a circumferentially extending concavity therein similar to that of the ink positioning roller 26. This concavity serves to assist in centering the ink on the peripheral surface 24a of roller 24 in a manner similar to that previously described in connection with roller 26. The concavity also desirably serves for keeping the fiber centered on the applicator roller for more uniform application of the ink. 
     As mentioned above, the primary use of machine 10 is the treatment of a plurality of moving strands of buffer coated glass fibers with a coating of curable viscous ink so as to rapidly and economically color code substantial quantities of glass fiber waveguides. 
     Ink 31 is desirably an ultraviolet curable ink containing no volatiles that would present undesired processing and environmental problems. The coating of ink applied to strands 14 is cured by passing the plurality of moving strands 14 through passageway 40 wherein they are exposed to ultraviolet radiation generated by one or more suitable sources thereof (not shown) contained in cabinet 41. This curing is accomplished almost instantly which allows the strands to be moved along at relatively fast speeds of up to about 150 meters per minute. 
     Ink applicator apparatus module 20 is likewise adapted to suitably coat the moving strands at relatively fast speeds. Use of this module 20 with its series of rollers allows for the discrete provision of precise amounts of ink 31 in order to form the relatively thin and substantially uniform coating thereof on strands 14. This apparatus permits continuous or intermittent coatings of ink of less than about 10 microns to be readily applied to strands 14. Furthermore, the speed of pump P is correlated with the rate of application of ink to the moving strand 14 so as to result in no accumulation of ink at the point of ink application to strand 14. The ink is applied and taken away by the moving strand 14 as fast as it is delivered thereto by ink applicator module 20. 
     A control console 50 (FIG. 1) houses the controls for determining the various machine functions including strand speed, dye color application, and curing operation. 
     In the drawings and specification, there have been disclosed typical preferred embodiments of the invention, and although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation.