Color changing system for spray dyeing

Abstract: A color changing system for spray dyeing comprises a pair of washing tubs (2) and a pair of spraying units (1). Each of the spray units (1) includes a nozzle/nozzles (5), a feed pipe (3) and a movable pipe (4). The spraying units (1) are alternately operated to spray dye liquid onto a fabric strip (17), and are washed in the washing tubs (2) to prepare for spraying new dye liquid onto the fabric strip (17).

Description: 1. Field of the Invention: This invention relates to a spray dyeing process for continuously dyeing a long strip of fabric (hereinafter called a "fabric strip") such as a slide fastener chain, slide fastener tape, surface fastener, ribbon, and the like by spraying dye liquid thereat, and more particularly to a system for changing dye colors by washing spray nozzles without interrupting the spray dyeing process. 2. Description of the Related Art: This invention relates to improvement of the invention disclosed in Japanese Patent Laid-Open Publication 2-307960. Heretofore the process of spray dyeing is well-known, in which dye liquid is sprayed onto a fabric strip. This spray dyeing is suitable to produce a good assortment of fabric strips in a small amount. The invention disclosed in the above Japanese Patent Laid-Open Publication relates to a method of washing spray nozzles for such spray dyeing, in which a pair of spraying units are used. When one of the spraying units is in operation, the nozzle of the other spraying unit is displaced from the fabric strip, so that the nozzle of the other spraying can be rinsed by washing liquid supplied to the nozzle. Thus the fabric strip is sectionally dyed in different colors without interrupting the spray dyeing process. With this spray dyeing, the washing liquid is supplied to the nozzles to rinse them, then being discharged in the air. The washing liquid mixed with the dye liquid floats around the fabric strip, which might be stained while it is being conveyed. EP-A-0 398 126, a document according to Art. 54(3) EPC, discloses a color-changing system for spray-dyeing, comprising:- at least first and second spraying units; each said spraying unit including a feed pipe, a movable pipe, at least one nozzle and selectively switchable supply means to supply said feed pipe selectively either with dye liquid or washing liquid, said movable pipe being connected to one end of said feed pipe to receive the dye liquid or washing liquid therefrom, said at least one nozzle being connected to said movable pipe to receive the dye liquid or washing liquid therefrom, said movable pipe being movable so as to move said at least one nozzle selectively into and out of a spraying position, and moving means for selectively moving said movable pipe, said supply means being interconnected with said moving means so that said feed pipe, said movable pipe and said at least one nozzle are supplied with the dye liquid, for a spraying step, when said at least one nozzle is in said spraying position, and with the washing liquid, to prepare for a subsequent spraying step, when said at least one nozzle is out of said spraying position; said first and second spraying units being interconnected so that, when said at least one nozzle of said first spraying unit is in said spraying position, said at least one nozzle of said second spraying unit is out of said spraying position, and so that, when said at least one nozzle of said second spraying unit is in said spraying position, said at least one nozzle of said first spraying unit is out of said spraying position. However, the nozzles of the spraying units of EP-A-0 398 126 tend sometimes not to be properly washed, because they are not immersed in washing liquid. Moreover, neither of EP-A-0 353 963 and GB-A-2 083 412 suggests immersion of spra in unit nozzles in washing liquid. SUMMARY OF THE INVENTION It is an object of this invention to provide a color changing system for the spray dyeing, in which the nozzles can be completely rinsed without staining the fabric strip and without interrupting the spray dyeing process. According to this invention, there is provided a color changing system for spray dyeing, according to claim 1. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic perspective view of a color changing system according to an embodiment of this invention; FIG. 2 is a cross-sectional view of the color changing system mounted in a dyeing chamber; FIG. 3 is a front view showing a modified arrangement of nozzles; and FIG. 4 is front view showing a still further modified arrangement of nozzles. DETAILED DESCRIPTION One embodiment of the invention will be now described , with reference to the accompanying drawings. A color changing system comprises a pair of dye spraying units 1, 1, and a pair of wash tubs 2, 2. The two dye spraying units 1, 1 are identical. When one of the spraying units 1, 1 is in operation, the other is being washed prior to spraying dye liquid of a different color. The spraying units 1, 1 are alternately operated to spray-dye the fabric strip without interruption. Therefore, operation of only one of the units is described hereinafter. A spraying unit 1 includes a pipe 3 for feeding either the dye or washing liquid, a movable pipe 4 communicating with the feed pipe 3, and nozzles 5 attached to one end of the movable pipe 4. The feed pipe 3 serves to supply the dye liquid and washing liquid to the nozzles 5. One end of the feed pipe 3 is connected to a dye liquid tank 7 and a washing liquid tank 8 via a select valve 6 as indicated by dot-and-dash lines in FIG. 1. The movable pipe 4 is in the shape of a letter "T", and is movably connected to an other end of the feed pipe 3. The nozzles 5 are attached to an end of a branch at the central portion of the movable pipe 4. The other end of the movable pipe 4 terminates in a gear 9, which is in engagement with a gear 11 connected to a drive shaft 10. The drive shaft 10 is set in motion by a non-illustrated motor. The gears 9, 11 turn forwards and backwards according to the movement of the drive shaft 10, thereby moving the nozzles 5 upwards and downwards. The nozzles 5 are reciprocated between a spraying position and the washing tub 2. In the spraying position, the nozzles 5 confront a fabric strip 17, and spray dye liquid onto said fabric strip 17. When the nozzles 5 are in the washing tub 2, they discharge washing liquid into the washing tub 2. In the spraying position, the nozzles 5 are arranged to confront the center line of the fabric strip which is continuously guided downwardly so that the dye liquid can be divergently and transversely sprayed onto the fabric strip 17. In the embodiment of FIG. 1, the nozzles 5 are vertically aligned. Although two nozzles 5 are used in the embodiment shown in FIG. 1, it is not necessary to have two nozzles. One or up to four nozzles may be used. The nozzles 5 may be arranged to spray the dye liquid onto either the front surface of the fabric strip 17 as shown in FIG. 1 or onto both the front and rear surfaces of the fabric strip 17 as shown in FIG. 2. FIG. 3 shows a modified arrangement of the nozzles of a pair of spraying units. Specifically, in the spraying position the nozzles 5 are placed so as to obliquely face the center line of the fabric strip 17, thereby enabling the nozzles to be moved promptly without interfering each other. The nozzle pairs of the two spraying units may be alternatively arranged as shown in FIG. 4. In this case, the nozzle pairs should be firstly withdrawn as indicated by straight arrows and then moved as indicated by oblique arrows. The pair of washing tubs 2 are symmetrically arranged under the spraying units 1, 1 and the movable pipes 4, 4. The nozzles of a spraying unit 1 are moved downwardly into the washing tub 2 to be steeped and washed therein. Specifically, the outer surface of the nozzles 5 is washed in the washing tub 2, and the inner surfaces of the nozzles 5, the feed pipe 3 and the movable pipe 4 are rinsed by washing liquid supplied via the select valve 6. The used washing liquid is received in the washing tub 2. The washing tub 2 should be always filled with the washing liquid to sufficiently cover the nozzles 5 and not to be scattered when washing the nozzles 5. The amount of the washing liquid in the washing tub is controlled by a feed pipe 12 and a drainpipe 13. In the embodiment of FIG. 1, two washing tubs 2 are respectively used for the pair of the spraying units 1, 1. However, it is also possible to use one large washing tub for both the spraying units 1, 1. In the embodiment shown in FIG. 2, the nozzles 5 and movable pipes 4 of the spraying units and the washing tubs 2 are mounted in a dyeing chamber 14 to prevent dye mist from being dispersed outwardly. The dyeing chamber 14 has a pair of lids 15, 15, which are opened and closed by a pair of liquid pressure cylinders 16, 16. The lids 15, 15 are kept closed during the spray dyeing, being opened to suck the residual dye mist from the dye chamber 14 when different dye liquid is to be used subsequently. Thus, the dyed fabric strip 17 can be kept from being stained. According to this invention, a pair of the spray units are associated with at least one washing tub, so that when one of the spray units is in operation, the other spray unit is standby with its nozzle(s) steeped in the washing tub(s). To dye the fabric strip in a different color, the spraying unit in operation is lowered while the nozzle(s) of the standby spraying unit is/are raised to the spraying position. Then new dye liquid is sprayed onto the fabric strip through the nozzle(s) of the other spray unit. Not only the inner surfaces of the feed and movable pipe but also the nozzle pairs can be completely washed in the washing tubs. The washing liquid containing the dye liquid is kept in the washing tub, so that the dyed fabric strip can be dyed as desired without being stained. Units outside the spray units will not be also stained. The spray-dyed fabric strip is then color-developed by steam, color-fixed, washed, dried, and brought forward as a colored product. At least a pair of the spraying units should be used according to this invention. Three or more spray units may be installed to perform dyeing and washing alternately. A plurality of long strips of fabric such as slide fastener tapes may be guided in rows to be spray-dyed simultaneously. With this invention, the spray dyeing is performed by a pair of the spraying units and at least a washing tub. The spraying units are alternately used so that when one of them is in operation, the other unit is standby in the washing tub where the outer and inner surfaces of the feed and movable pipes as well as the nozzle(s) are washed. The liquid for washing these components is kept in the washing tub not to be dispersed in the air as mist. Therefore, the dyed fabric strip will not be stained, and new dye liquid can be sprayed via the washed nozzles to dye the fabric strip clearly and beautifully.

Claims: A color-changing system for spray-dyeing, comprising:- at least first and second spraying units (1); each said spraying unit (1) including a feed pipe (3), a movable pipe (4), at least one nozzle (5) and selectively switchable supply means (6, 7, 8) to supply said feed pipe (3) selectively either with dye liquid or washing liquid, said movable pipe (4) being connected to one end of said feed pipe (3) to receive the dye liquid or washing liquid therefrom, said at least one nozzle (5) being connected to said movable pipe (4) to receive the dye liquid or washing liquid therefrom, said movable pipe (4) being movable so as to move said at least one nozzle (5) selectively into and out of a spraying position, and moving means (9, 10, 11) for selectively moving said movable pipe (4), said supply means (6, 7, 8) being interconnected with said moving means (9, 10, 11) so that said feed pipe (3), said movable pipe (4) and said at least one nozzle (5) are supplied with the dye liquid, for a spraying step, when said at least one nozzle (5) is in said spraying position, and with the washing liquid, to prepare for a subsequent spraying step, when said at least one nozzle (5) is out of said spraying position; said first and second spraying units (1) being interconnected so that, when said at least one nozzle (5) of said first spraying unit (1) is in said spraying position, said at least one nozzle (5) of said second spraying unit (1) is out of said spraying position, and so that, when said at least one nozzle (5) of said second spraying unit (1) is in said spraying position, said at least one nozzle (5) of said first spraying unit (1) is out of said spraying position; said color-changing system for spray-dyeing having at least one washing tub (2) filled with washing liquid, and said movable pipe (4) of each of said first and second spraying units (1) being movable so as to move said at least one nozzle (5) connected thereto out of the spraying position into the said, or a said, washing tub (2) filled with washing liquid, so as to immerse said at least one nozzle (5) completely in the washing liquid. A color-changing system according to claim 1, adapted for spray-dyeing a fabric strip, wherein each said spraying unit (1) comprises at least two said nozzles (5), said at least two nozzles (5) being disposed so that when a spraying unit (1) is in said spraying position dye liquid is simultaneously sprayed onto said front surface and onto a back surface of said fabric strip (17). A colour changing system according to claim 1 or 2 and wherein said washing tub(s) (2) and said spraying units (1) are mounted in a dyeing chamber (14), said dyeing chamber comprising a pair of closable lids (15). A method of spray dyeing a fabric strip (17) using a colour changing system according to any preceding claim, said method comprising the steps of: - a) moving the nozzle(s) (5) of a first spraying unit (1) from said washing tub(s) 2 to a first spraying position; b) spraying dye liquid of a first colour onto said fabric strip (17); c) moving the nozzle(s) 5 of said first spraying unit 1 into said washing tub(s) (2), and moving the nozzle(s) 5 of a second spraying unit (1) from said washing tub(s) 2 into a second spraying position; and d) spraying dye liquid of a second colour onto said fabric strip (17) from said nozzle(s) 5 of said second spraying unit 1, while washing said nozzle(s) of said first spraying unit 1with washing liquid.

Inventors: YAMAKITA YOSHIMICHI, YAMAKITA, YOSHIMICHI
Applicants: YKK CORP, YKK CORPORATION
Application year: 1991
Main classification: D06B23
IPC codes: D06B11, D06B1, D06B23