IE83517B1 - Printing of pvc coated fabric material - Google Patents

Description

The present invention relates to a method of printing a PVC coated fabric material.

The method is of the general type comprising feeding a continuous web on a conveying system comprising at least one drive drum roller and a plurality of idler rollers through a number of workstations.

Such PVC coated fabric is made by applying a topping PVC material followed by a foamed paste layer and a laminating material onto a release face of a paper substrate material. A fabric backing layer is then applied over the laminating layer to form a composite. The paper substrate is then removed from the composite.

Such PVC coated fabric materials are used extensively for upholstery and for the manufacture of many products such as suitcases, cases and boxes generally and thus are often required to have consistent colouring. The colouring of such PVC coated fabric materials is very difficult in that, by its very nature, the material cannot be dyed but must be printed subsequent to manufacture. The problem with the printing is that it is vital that the inks or ink be applied accurately and consistently.

Any misalignment of the web when being led through the various workstations almost inevitably causes difficulty in the printing and subsequent lacquerlng.

Further, since very often such printing takes place in relatively short batches, it is essential to be able to vary colours quickly so as to provide the necessary flexibility in manufacture.

The present invention is directed towards these objects.

S1a1emen1s.n1.lmLen1inn According to the invention there is provided a method of printing a PVC coated fabric material of the type comprising feeding a continuous web of the material on a conveying system comprising at least one drive drum roller and a plurality of idler rollers through a number of workstations comprising the steps of:- delivering web from a roll through an accumulator; delivering the web across two in-line alignment rollers mounted together on a separate pivotal carriage; sensing the position of the edge of the web downstream of the alignment rollers by delivering portion of a constant jet of air against one face of the web adjacent its edge; collecting the air transmitted across the web; measuring the amount of air collected as an indication of the edge position of the web; causing pivotal movement of the carriage in response to the edge position sensed; leading the web to a printing station; applying printing ink onto a front face of the web by leading the web between two vertically arranged nipping rollers, the lower roller forming a printing roller being partially submerged in an ink retaining bath and applying a scraping blade against the lower nipping roller to remove excess ink; heating the front face of the web to a temperature within the range 60 to 809C; delivering air onto the front face of the web to dry and cool it; repeating steps (b) to (f) inclusive to re-align the web; (l) leading the web to a Iacquering station; (m) applying lacquer to the front face of the web by leading the web between two rollers, namely a nipping roller and a lacquer applying roller, the nipping roller being of an elastic material to apply a pressure against the web and maintaining contact between the lacquer and the nipping roller by urging a diametrically opposed idler rolled of a rigid material against the nipping roller, the lacquer applying roller being partially submerged in a lacquer containing bath for the take up of lacquer thereon and then scraping excess lacquer from the face of the web by applying a blade to the web; (n) heating the front face of the web to a temperature between 85 and 115‘—°C to cure the lacquer; (o) cooling the web by air drying as it is led through rollers to a take~off station; and (p) rolling up the web of the lacquered and printed PVC coated mmmmmaw.

By ensuring a very accurate alignment of the web, it is possible to provide extremely accurate printing. Various other methods have been used in the past for aligning the web such as, for example, optical methods and other sensors which unfortunately were not sufficiently accurate to provide the necessary control of the web through the various stations. in particular, it was found that without this accurate alignment through the printing station, the printing was inaccurate with subsequent difficulties. it has been found necessary to control very accurately the amount of ink applied at each workstation as well as the amount of lacquer since excess ink or excess lacquer tends to give an uneven and unacceptable quality of product. Originally, various take-off rollers and the like have been provided to remove excess ink and lacquer, however, again, these did not prove particularly successful. Thus, the use of a scraping blade was found to be most advantageous. in one embodiment of the invention, after printing, the front face of the web, the web is realigned by carrying out steps (b) to (f) inclusive and then the steps of printing the front face of the web, namely, steps (g) to (j) are repeated. it has been found that it is particularly advantageous to be able to carry out a second printing operation immediately after the first printing operation, either to provide a totally different colour to the fabric or to provide another coat of the previously applied printing ink. After once printing the front face of the web, the steps of printing the front face of the web, namely steps (g) to (j) inclusive are repeated. The advantage of this is again that more flexibility can be provided. Also, by having two printing stations together intermediate alignment allows further flexibility. ideally, the front face of the web is lacquered more than once by repeating steps (l) to (o) inclusive. By lacquering more than once, it is possible either to change the lacquering material to provide a suitable fixation of the printing ink or more importantly to apply relatively thin coats of lacquer so as to build up the lacquer coat which will provide further durability.

Ideally, the method comprises stretching the web as it is treated. By stretching the web, it is possible to ensure that a fully consistent product is provided because when the stretching is relaxed, the web will assume a consistent colour and texture. it has been found very important to keep the temperature of the heating of the web after printing within relatively close limits and ideally, the range should be of the order of 65 to 7590. By ensuring that the ink is fixed correctly, a consistent colour of printing is achieved. Further, ideally, the heating of the web after lacquering is carried out at approximately 1009C. Again, substantially the same considerations have been discovered in relation to lacquering, as with printing and lacquering, must be carried out within relatively close limits. ideally, the web is fed at the rate of between 10m and 20m per minute and preferably at the rate of between 14m to 16m per minute. Again, it has been found that while it is desirable to have the maximum production possible, if the web is fed too quickly through the machinery, inconsistent printing and lacquering occurs. However, the combination of stretching the web at a relatively fast speed can be achieved with the present invention by the careful control of the temperatures.

Further, the invention provides a method in which when applying lacquer, the scraping blade subtends an angle of approximately 559 with the web. This appears to be an extremely efficient angle at which the blade should be orientated to ensure adequate removal.

Ideally, prior to printing on the front face of the web, a flame retardant material is applied to the rear face. This has considerable safety implications.

Further, the invention provides a method comprising:- delivering the rolled web of lacquered and printed PVC coated fabric material to an unrolling station; placing a core on the web adjacent a free end thereof; rotating the core and web to wrap some of the web around the core; tipping the rolled core away from the rolled web to allow a length of web to be exposed; placing adhesive tape on the web intermediate the rolled core and the rolled web; cutting the web to leave the adhesive tape on the web on the core; placing a thermoplastics sheet wider than the web onto the web in contact with the adhesive; re-rolling the web and the sheet until the sheet completely surrounds the web and core; and heat sealing the thermoplastics sheet to itself to cut the sheet and to encompass the web on the core.

This is an extremely efficient way of packing relatively short lengths of printed PVC fabric for subsequent use. The shrink wrapping is automatic and provides a very well protected product with minimal handling costs.

Ideally, the heat shrinking occurs at between 100 to 13090. This has been found to be a particularly suitable temperature.

I: .| In . . H I I.

The invention will be more clearly understood from the following description of some embodiments thereof, given by way of example only, with reference to the accompanying drawings in which:- Fig. 1 is a side view of a printing and lacquering plant according to the invention, Figs. 2 and 3 are enlarged views of the printing and lacquering plant of Fig. 1, Fig. 4 is a perspective view showing the progression of a web through the printing and lacquering plant, Fig. 5 is an enlarged view of Fig. 4, Fig. 6 is a perspective view of an alignment station according to the invention, Fig. 7 is a perspective view of the alignment station of Fig. 6 with the web removed, Fig. 8 is a perspective view of a printing station according to the invention, Fig. 9 is a side view of the printing station, Fig. 10 is a perspective view of a lacquering station according to the invention, Fig. 11 is a side view of the lacquering station, Fig. 12 is a side view of a packing machine, Figs. 13 and 14 are enlarged views of an infeed station forming part of the packing machine, Fig. 15 is an enlarged view of the infeed station and the gluing and cutting station forming part of the packing machine, Figs. 16 to 21 are enlarged side views of shrink wrapping and take-off stations forming part of the packing machine, and Fig. 22 (A) to (L) is a diagrammatic view showing operation of the packing machine.

Referring to the drawings and initially to Fig. 1, there is provided a printing and lacquering plant, indicated generally by the reference numeral 1. The printing and lacquering plant comprises an infeed station 2 feeding a stretching and identification station 3 which in turn feeds an alignment station 4 feeding printing stations 5, a further alignment station 4, further printing stations 5, a further alignment station 4 feeding a lacquering station 6 to finally, a take-off station 7. The web is identified throughout by the reference numeral 10 and has a front face 9 and a rear face 8.

Referring specifically to Figs. 3 to 5 inclusive, the infeed station 2 comprises a web roll support 11 feeding an accumulator 12 having upper and lower rollers 13 and 14 respectively movable towards and away from each other to allow rolls of web 10 to be changed without stopping the operation. The accumulator 12 in turn feeds a pre- stretching station 15 provided by a number of rollers 16, some of which are nipping rollers, in the sense that there is one mounted above each other to nip the web 10 therebetvveen. In the drawings, all these rollers are identified by the reference numeral 16. Within the station 15, there is provided a printer, indicated generally by the reference numeral 17, for printing identification and other indicia as well as fire retardant material on the rear face 8 of the web 10. Accuracy is not a factor with the printer 17.

Referring now to Figs. 6 and 7, the alignment station 4 comprises a support framework 25 carrying a pivot mounting 26 on which is mounted a sub-frame 27 which in turn carries a pair of alignment rollers 28. A pneumatic ram 29 is provided for pivoting the sub-frame 27 about the pivot mounting 26 and thus for alignment of the web 10. Mounted below the support framework 25 by a cantilevered support 31 is a sensor 32 having a bifurcated arm 33. One bifurcated arm 33 carries a nozzle (not shown) for the delivery of a jet of air against the edge of the web 10, while the other arm 33 carries a collector (not shown) for the reception of any air delivered across the edge of the web. Control means are provided within the sensor 32 for measuring the amount of air collected and thus the position of the edge of the web.

The sensor 32 is connected by suitable control means to operate the pneumatic ram 29.

Referring now to Figs. 8 and 9, each printing station 5 comprises a pair of nipping rollers, namely, an upper nipping roller 40 and a lower nipping roller 41, partially submerged in an ink retaining bath 42. The upper nipping roller 40 is manufactured from rubber and is secured in position and retained by a solid further additional idler roller 43. A scraper blade 45 is mounted against a lower nipping roller 41 to ensure that a constant film of ink is taken up by the nipping roller 41.

Referring to the drawings and specifically to Figs. 10 and 11, the Iacquering station 6 comprises an upper Iacquering roller 50 having a plurality of upwardly arranged projections 51 to grip the web 10 therebetween it and a lower printing roller 52 partially submerged within a bath of lacquer 53. A scraper blade 54 is mounted in contact with the web 10 and is sited above the lacquer bath 53. in operation, a roll carrying a web of PVC coated fabric material is mounted on the web roll support 11, is then led to the accumulator 12 from the infeed station 2 to the stretching and identification station 3 where the web 10 is stretched and the back of the web is covered with a fire retardant material by the printer 17. Also, at this stage, any identification of the material is printed on the rear face 8 of the web 10. Then the web 10 is delivered to the first alignment station 4 where the position of the edge of the web downstream of the alignment rollers 25 is sensed by delivering a constant jet of air against the edge thereof such that only some of the air is transmitted across to the other end of the bifurcated arm 33 for collection so that the amount of air collected is an accurate measure of the position of the edge of the web 10 on the rollers. Then, this measurement is used as an indication of the edge position and this is then sent to the controller forming part of the sensor 32 which controls the pneumatic ram 29 to cause the carriage 27 to pivot about the pivot mounting 26 to accurately align the web 10.

The accurately aligned web 10 is then delivered to the first printing station 5 where it is delivered between the upper nipping roller 40 and the lower nipping roller 41 such that a thin layer of ink is applied to the front face 9 and the web 10 is then delivered into the heater 46 where it is heated between 60 to 809 and preferably between 65 to 75‘—’C to fix the ink onto the web. Then it is delivered to the cooling chamber 47 where jets of air are delivered against the front face 9 of the web 10 to cool it. Depending on whether it is required, printing is again carried out at the next printing station 5 and the web 10 is then delivered to a further alignment device 4, to further printing stations 5 and then to a further alignment device 4. Depending on the particular application, the number of printing stations 5 that will be used will vary from one to four. One of the advantages of having additional printing stations is that it will allow printing stations 5 to be cleaned and generally maintained by simply, if necessary, leading the web 10 through a bypass idler roller to avoid any particular printing station. it will be easily appreciated that, for example, the web can at any stage be made to bypass any particular printing station.

The web 10 is now led to the lacquering station 6 between the upper lacquering roller 50 and lower roller 52 and then excess lacquer is removed by the scraper blade 54 before the web 10 is then delivered through the heater 55 and out for cooling by leading it across rollers. Then it is delivered to the take-off station 7 where it is further stretched and rolled up on the take-off support 60. -10..

The web will normally be delivered at approximately 15m per minute through the printing and lacquering plant. Speeds of between 10 and 20 m per minute can be used in certain circumstances. in many instances, the roll is delivered in relatively large quantities to customers, however, in many instances, the web 10 has then to be cut into smaller lengths of web 10 and usually then rolled onto a core. This is carried out in the packing machine as illustrated in Figs. 12 to 19 inclusive.

Referring to Figs. 12 to 22 inclusive, there is illustrated a packing machine indicated generally by the reference numeral 100 comprising an infeed station 101, a control station 102, a rolling station 103, a gluing and cutting station 104, a shrink wrapping station 105 and a take-off station 106. The infeed station 101 comprises a web roll support 110 and incorporates again idler rollers 16 mounted on a framework 111 pivotally mounted on a support 112 and movable thereon by a ram (not shown). The web 10 is led from the infeed station 101 beneath the control station 102 which comprises a computer 115 connected to various portions of the packing machine 100. The web 10 is led underneath the control station 102 to the rolling station 103.

The rolling station 103 (see Fig. 13) comprises a magazine 120 mounted by means of uprights 121 above a support table 122. Also mounted on the support table 122 are idler rollers 123 and 124. Means are provided to pivot the idler rollers 123 and 124 so that the idler roller 123 lies above the idler roller 124. This means is not shown. The magazine mounts core dispensing arms 125 and a roller actuator 126 is pivotal about an arm 127. All the pivoting is done by means of pneumatic rams (not shown).

The gluing and cutting station 104 (see Fig. 15) comprises a adhesive tape dispensing head 130 mounted above the support table 122 and reciprocal transversely thereon. A cutter blade 131 is also mounted above the support table 122 and again reciprocal transversely thereon. A pair of idler rollers 132 and 133 are mounted on the support table 122 and are again pivotal such that the idler roller 132 can pivot relative to the idler roller 123 so as to raise the idler roller 132 above the idler roller 133. This is done by means of pneumatic rams (not shown).

Referring specifically to Figs. 16 to 21, the shrink wrapping station 105 comprises a support framework 140 above the support table 122 carrying a heat sealing mechanism 141 raised up and down on the support framework 140 by a motor 142.

The heat sealing mechanism incorporates hot air end sealers 143 and a transverse heat sealing bar 144, all of convention construction. Mounted below the heat sealing mechanism 141 is a reel support 145 carrying plastics film material 146. A pivotal end stop 147 is provided beneath the heat sealing mechanism 141 as is a drive roller 148. Various end sensors for sensing the end of the web 10 are provided but are not illustrated.

Again referring to Figs. 16 to 21 inclusive, the take-off station 106 comprises a support 150 mounting a pivoting chute 151 and a pivotal cradle 152 actuated by a ram 153.

In operation and referring specifically to Fig. 22, a web roll is placed on the web roll support 110 and the framework 111 is pivoted sufficiently to provide a suitable tension on the web 10. The web 10 is led initially, when the first web is placed on the packing machine 100, through the various idler rollers 16 to the rollers 123 and 124 where a small amount of the web 10 is pulled between these rollers. Then the core dispensing arms 125 carrying one core identified by the reference numeral 128 is lowered onto the web 10. Then, the core dispensing arms 125 are retracted and the roller actuator 126 is pivoted about the arm 127. The roller actuator 126 then rolls the web 10 about the core 128 (see Figs. 22(b)) until the requisite amount of web 10 has been wrapped around the core 128. Then, the roller actuators 126 are stopped and retracted. The roller 123 is then pivoted upwards which causes the core 128 carrying the rolled up web 10 to pivot away from the rollers 123 and 124 to assume the position above the two rollers 132 and 133 as illustrated in Fig. 22(c). Then, the adhesive tape dispensing head 130 is operated to place tape on the exposed length of web and then the cutter blade 131 is used to cut the web. The web 10 is then, together with the core 128, again tipped by the roller 132 towards the shrink wrapping station 105 where it is then tipped against the pivotal end stop 147 where it is rolled up until most of the free end of the web 10 has been rolled. Then the plastics film material 146 is dispensed across the web to adhere thereto (Fig. 22(f)). it is then rolled around further until sufficient plastics film material 146 is wrapped around the core and web. Then, the heat sealing mechanism is lowered and then plastics film is heat sealed to itself and cut—off. Then, the two ends are heat sealed and the web is totally wrapped, as can be seen in Fig. 22. Then, the pivotal end stop 147 is pivoted downwards and the rolled web is delivered onto the pivotal chute 151 (see Fig. 18).

Then the pivotal chute 151 is pivoted (see Fig. 18 and 19) to cause the rolled web to be deposited in the pivotal cradle 152 (see Fig. 20). Then, the pivotal cradle is pivoted downwards as illustrated in Fig. 21. in the specification the terms “comprise, comprises, comprised and comprising” or any variation thereof and the terms “include, includes, included and including” or any variation thereof are considered to be totally interchangeable and they should all be afforded the widest possible interpretation.

The invention is not limited to the embodiments hereinbefore described but may be varied in both construction and detail. V

Claims (1)

1. A method of printing a PVC coated fabric material of the type comprising feeding a continuous web of the material on a conveying system comprising at least one drive drum roller and a plurality of idler rollers through a number of workstations comprising the steps of:— delivering web from a roll through an accumulator; delivering the web across two in-line alignment rollers mounted together on a separate pivotal carriage; sensing the position of the edge of the web downstream of the alignment rollers by delivering portion of a constant jet of air against one face of the web adjacent its edge; collecting the air transmitted across the web; measuring the amount of air collected as an indication of the edge position of the web; causing pivotal movement of the carriage in response to the edge position sensed; leading the web to a printing station; applying printing ink onto a front face of the web by leading the web between two vertically arranged nipping rollers, the lower roller forming a printing roller being partially submerged in an ink retaining bath and applying a scraping blade against the lower nipping roller to remove excess ink; heating the front face of the web to a temperature within the range 60 to 809C; delivering air onto the front face of the web to dry and cool it; repeating steps (b) to (f) inclusive to re-align the web; leading the web to a lacquering station; applying lacquer to the front face of the web by leading the web between two rollers, namely a nipping roller and a lacquer applying roller, the nipping roller being of an elastic material to apply a pressure against the web and maintaining contact between the lacquer and the nipping roller by urging a diametrically opposed idler rolled of a rigid material against the nipping roller, the lacquer applying roller being partially submerged in a lacquer containing bath for the take up of lacquer thereon and then scraping excess lacquer from the face of the web by applying a blade to the web; heating the front face of the web to a temperature between 85 and 11590 to cure the lacquer; cooling the web by air drying as it is led through rollers to a take-off station; and rolling up the web of the lacquered and printed PVC coated fabric material. A method as claimed in claim 1, in which after printing the front face of the web, the web is realigned by carrying out steps (b) to (f) inclusive and then the steps of printing the front face of the web, namely, steps (g) to (j) are repeated. A method as claimed in claim 1 or 2, in which after once printing the front face of the web, the steps of printing the front face of the web, namely steps (g) to (j) inclusive are repeated. A method as claimed in any preceding claim, in which the front face of the web is lacquered more than once by repeating steps (l) to (0) inclusive. A method as claimed in any preceding claim comprising stretching the web as it is treated. A method as claimed in any preceding claim in which the heating of the web after printing is carried out at a temperature within the range 65 to 75‘—’C. A method as claimed in any preceding claim, in which the heating of the web after lacquering is carried out at approximately 1009C. A method as claimed in any preceding claim in which the web is fed at the rate of between 10m and 20m per minute. A method as claimed in any of claims 1 to 7, in which the web is fed at the rate of between 14m to 16m per minute. A method as claimed in any preceding claim, in which when applying lacquer, the scraping blade subtends an angle of approximately 559 with the web. A method as claimed in any preceding claim, in which prior to printing on the front face of the web, a flame retardant material is applied to the rear face. A method as claimed in any preceding claim comprising:- delivering the rolled web of lacquered and printed PVC coated fabric material to an unrolling station; placing a core on the web adjacent a free end thereof; rotating the core and web to wrap some of the web around the core; tipping the rolled core away from the rolled web to allow a length of web to be exposed; placing adhesive tape on the web intermediate the rolled core and the rolled web; cutting the web to leave the adhesive tape on the web on the core; placing a thermopiastics sheet wider than the web onto the web in contact with the adhesive; re-rolling the web and the sheet until the sheet completely surrounds the web and core; and heat sealing the thermopiastics sheet to itself to cut the sheet and to encompass the web on the core. A method as claimed in claim 12, in which the heat shrinking occurs at between 100 to 130‘—’C. A method substantially as hereinbefore described with reference to the accompanying drawings. A printed PVC coated fabric material produced in accordance with the method of any preceding claim.