APPARATUS AND METHOD FOR SPRAY TREATING FABRIC

Abstract

A spray coating apparatus is provided, wherein a nozzle is arranged to traverse a fabric in one direction whilst simultaneously spraying and oscillating in another direction. The fabric is spray coated with a first pass having a spray zone having uneven distribution in the direction of oscillation, and particularly with a greater density of fluid coverage toward the centre of the spray zone than an edge. The nozzle forming a second and subsequent pass that is off-set from the first and each subsequent pass respectively. The second and each subsequent pass being arranged to overlap with a portion of the previous pass, thereby providing an improved distribution of the spray coating. Moreover, because the spray coating is incremental, the method is easily adaptable to integrate with an ink jet printing process.

Claims

1. A method of coating a substrate comprising causing at least one nozzle to at least partially traverse a length of fabric in one direction whilst causing fluid to be emitted and thereby to be coated onto the fabric unevenly in a direction across the traverse in a first spray zone and causing at least one nozzle to subsequently traverse a second length of fabric in a second direction whilst causing fluid to be emitted and thereby to be coated onto the fabric unevenly in a direction across the traverse in a second spray zone, wherein the first and second spray zones are arranged to overlap.

2. The method as claimed in claim 1 in which the method comprises oscillating the nozzle in the direction across the traverse.

3. The method of claim 2, wherein the method comprises causing the nozzle to oscillate in a swinging motion so that the spray zone is caused to have a heaviest distribution of fluid in the centre of oscillation and a lightest distribution of fluid at the two extents of the oscillation.

4. The method of claim 2, wherein the method comprises arranging the nozzle to have a primary fluid emission direction that is angled to the vertical so that the spray zone is caused to have the heaviest distribution of fluid nearest the nozzle and the lightest distribution of fluid furthest form the nozzle.

5. The method of claim 4 comprising causing the nozzle to be oscillated whilst spraying.

6. The method as claimed in claim 1 comprising causing coating onto the substrate with the at least one nozzle as a first spray zone and then causing relative movement of the fabric and the nozzle and then causing a further traverse of the nozzle and further simultaneous oscillation of the nozzle to coat a second spray zone, with there being a partial overlap of coating between the first and second spray zones.

7. The method as claimed in claim 1 comprising causing at least part of the traverse movement to be in a direction perpendicular to the length of the fabric over at least part of the traverse.

8. The method as claimed in claim 1 comprising varying the amount of fluid being emitted during different parts of the oscillation movement.

9. The method as claimed in claim 5 wherein the traverse direction of the first spray zone and the traverse direction of the second spray zone are opposite to each other.

10. A spray coating apparatus arranged, in use, to coat onto a substrate comprising a carriage carrying a nozzle, the carriage being arranged, in use, to carry the nozzle in a first direction and at least partially traverse a fabric with the nozzle being arranged to emit an uneven distribution of fluid across the traverse.

11. The spray coating apparatus of claim 10, wherein the nozzle is mounted to the carriage with an oscillator arranged, in use, to cause the nozzle to be oscillated back and forth in a second direction, and the apparatus comprising fluid supply means to supply fluid to the nozzle so that fluid is sprayed from the nozzle as it simultaneously traverses and oscillate.

12. The spray coating apparatus as claimed in claim 11 in which the carriage is arranged to carry the nozzle in a first direction which is perpendicular to the second direction of oscillation.

13. The spray coating apparatus as claimed in claim 11 in which the apparatus includes a movement means to move the fabric relative to the nozzle.

14. The spray coating apparatus as claimed in claim 11 including at least two nozzles each carried by a carriage and caused to at least partially traverse the fabric in one direction and each nozzle including an oscillator arranged to cause fluid to be emitted whilst simultaneously traversing and oscillating.

15. The spray coating apparatus as claimed in claim 11 including a controller arranged, in use, to control any one or more of the extent of oscillation of the oscillator, the frequency of oscillation of the oscillator, the speed of movement of the carriage, the rate of fluid being emitted by the nozzle or the distance between the nozzle and a fabric.

16. The spray coating apparatus as claimed in claim 11 in which the nozzle is pivotally mounted to the carriage.

17. The spray coating apparatus as claimed in claim 16 in which the oscillator includes a reciprocating lever connected to the nozzle at a location spaced from the pivotal connection of the nozzle.

18. The spray coating apparatus as claimed in claim 17 in which the reciprocating lever is pivotally mounted on the nozzle and the lever, in use, is caused to reciprocate by a further lever pivotally connected to the reciprocating lever, the further lever also being pivotally connected to a rotating member at a distance from the pivotal connection of the rotating member.

19. The spray apparatus as claimed in claim 18 in which the rotating member is caused, in use, to rotate by frictionally engaging a belt of the carriage, which belt effects the traverse movement of the nozzle.

20. The spray apparatus as claimed in claim 16 including a motor arranged, in use, to cause the nozzle to reciprocate.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0057] For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings in which:

[0058] FIG. 1 shows a known apparatus of pre-treating fabric prior to printing;

[0059] FIG. 2 shows a representation of lint or dust trapped between the ink and fabric layers;

[0060] FIG. 3 shows a side view of an apparatus for treating and printing on fabric;

[0061] FIGS. 4, 5 and 6 show top, front and back views of the apparatus of FIG. 3, respectively;

[0062] FIG. 7 shows a flow diagram of the treatment and printing processes; and

[0063] FIG. 8 shows a cleaning station;

[0064] FIGS. 9a to 9c show the operation of a dancing roller;

[0065] FIG. 10 shows a treatment spraying station;

[0066] FIGS. 11a and 11b show a heating station and the movability of the heating unit;

[0067] FIG. 12 is a side view of an spray coating station,

[0068] FIG. 13 is a plan view of one embodiment of a spray coating station,

[0069] FIG. 14 is a schematic view of an alternative nozzle arrangement; and

[0070] FIG. 15 is a schematic view of an alternative nozzle oscillation arrangement.

DESCRIPTION OF EMBODIMENTS

[0071] FIG. 3 shows a side view of a fabric treatment apparatus (100). Fabric (10) is fed (preferably as a roll) into a cleaning station (20) provided at the input end (A) of the apparatus (100). The cleaning station (20), as shown more clearly in FIG. 8, comprises air suction units incorporating a high pressure water supply and an adhesive coated roller (24) that removes lint or loose debris such as dust from the fabric. Air suction units (22) operate by vacuum effect to clean the adhesive roller and detach the loose material temporarily adhered to the roller (24) as the roller (24) rotatably contacts the fabric (10). The air suction units (22) remove the loose debris from the roller (24) so that the roller (24) can continue to effectively adhere debris from the fabric (10). The suction units (22) move along the roller (24) in a traverse direction to the direction of fabric (10) movement as shown in FIG. 5. The air suction units (22) therefore move in an axial direction parallel to the longitudinal axis of the roller (24) and effectively sweep the rollers (24) as they go. Preferably, the movement of the fabric (10) through the cleaning station (20) is substantially constant or is at least continuous so that no breaks in fabric (10) movement occur. This allows the fabric (10) to be continually fed through the system (100) without interruption. However, in alternative embodiments, the roller is cleaned off-line.

[0072] Once the fabric (10) has been cleaned, the fabric (10) is fed towards a dancing roller (30), the function of which is more clearly shown in FIGS. 9a to 9c. The dancing roller (30) converts the continuous motion of the fabric (10) exiting the cleaning station (20) into intermittent motion for supply to the rest of the apparatus (100). This allows the treatment process to be integrated as one with a printing process comprising an inkjet printer. The dancing roller (also known as an accumulator) is a term of the art and its general operation and effect is known. However, the operation in this current disclosure is briefly described in FIGS. 9a to 9c.

[0073] FIGS. 9a to 9c show the dancing roller (30) in operation. Fabric (10) is divided into four lengths (10a,10b,10c,10d). Each length represents a time block of unity and is therefore equal in length when a constant feeding speed is used. The dancing roller (30) has a displaceable axis so that the dancing roller (30) axis moves with respect to the axes of the cleaning rollers. As the fabric (10) is fed towards the dancing roller (30), the dancing roller (30) moves away from adjacent rollers in a downward direction (C1) as shown in FIG. 9b. The downward motion is simultaneous with the feeding motion and preferably operates at the same velocity. This allows one end of the first length of fabric (10a) to remain effectively stationary. As shown in FIG. 9c, the dancing roller (30) continues to move downwards as more fabric (10) is fed from the adjacent roller. This ensures that the fabric (10) does not slacken. Once three time periods have elapsed, the dancing roller (30) returns to the initial position in an upward direction (C2) as shown in FIG. 9d. This allows the three lengths of fabric (10a,10b,10c) to be fed towards the next station. Advantageously, the dancing roller (30) converts continuous motion to intermittent motion so that an inkjet printer can be integrated with a pre-treatment station (20).

[0074] Referring back to FIG. 3, once the fabric (10) leaves the dancing roller (30) the fabric (10) is sent to the treatment station (40). The treatment station (40), as shown more clearly in FIG. 10, comprises a moveable treatment zone (i.e. a spraying zone) is delineated by the extent of fluid spraying by the nozzles (42) on to the fabric (10). The spraying zone moves by an arm (46) in a transverse direction (D) across the width of the fabric (10), as shown in FIG. 4. Here, the nozzles (42) spray fluid, i.e. pre-treatment chemicals onto one side of the fabric (10) only (i.e. the top side), while moving back and forth in a direction orthogonal to the direction of fabric (10) movement through the apparatus (100). A mechanical atomisation nozzle may be used which avoids the use of air. This allows smaller droplets to be sprayed towards the fabric (10) so that a consistent distribution of treatment fluid is transferred onto the fabric (10). During the fluid spraying stage, the fabric is held substantially constant due to the movement of the dancing roller (30) even though the fabric (10) is continuously fed through the cleaning station (20).

[0075] The spraying zone is arranged such that the fabric (10) in contact with rollers (48) is not sprayed onto because contact with the rollers (48) can affect the integrity of the fabric (10) causing localised deformation compared to regions not in contact with the rollers (48). Therefore, only the unsupported fabric (10) is sprayed. That is, the spraying zone is arranged to act on an area between two supporting rollers. The duration, flow rate, pressure, volume, and average droplet size distance of the spray can be controlled in order to intimately affect the transfer or pre-treatment chemical to the fabric (10). For example, a pressure of between 50-100 bar can be used with or without a mechanical atomisation nozzle. However a pressure of between 20 and 45 bar has been found to work well and in particular around 30-35 bar. A high velocity spray may be used. The spray may be provided as a fine mist of vapour. Therefore, the penetration distance into the fabric (10) from one side of the fabric (10) can be varied. For example, a penetration level between 50-75% can be easily achieved. To prevent the spread of any excess fluid, a barrier (44) is placed below the fabric (10). In addition to the pre-treatment process a post-treatment process may be used. The post-treatment process may transfer chemicals onto the fabric (10) in order to make the fabric (10) water repellent.

[0076] Advantageously, the treatment station (40) has the ability to control the penetration level of the treatment fluid by, for example, varying the speed of movement, the pressure, volume, flow rate of fluid ejection and the number of nozzles. This means that there is no need for a mangle to draw excess fluid out of the fabric (10), which helps to make the apparatus (100) more compact and efficient. There is also no need to submerge the fabric (10) in a fluid bath, which improves the quality control of the fluid and avoids the need to store treatment fluid in a reservoir. Furthermore, rollers are not directly exposed to the treatment chemicals during spraying.

[0077] FIG. 12 shows an exemplary spray coating station (240) wherein a nozzle (250) is mounted to traverse the fabric in one direction whilst simultaneously oscillating in a back-and forth motion in a second direction. Here, the nozzle is arranged to at least partially traverses the fabric (10) to cause fluid (252) to be emitted thereby coating onto the fabric (10) through gravity. The nozzle is caused to oscillate as shown by the arrows (254) whilst fluid is being emitted. The spray zone of the nozzle is increased by the oscillation, whilst also allowing the density distribution in the oscillation direction to be unevenly distributed such that fabric under the centre of the oscillation is coated with a greater density of fluid than fabric towards the edges of the spray zone. After the nozzle has completed a traverse, the fabric is arranged to move relative to the nozzle, for instance by an increment in the length direction of the fabric. The nozzle can then make a return traverse to coat a second and subsequent spray zone on the fabric. However, the nozzle may be arranged to step along the fabric to make multiple passes, before indexing the fabric forward. Moreover, multiple nozzles may be provided and the fabric stepped a greater distance between each pass or passes of the nozzles. By overlapping the adjacent spray zones, it has been found that the unevenness of each spray zone can be compensated, and a more even complete coating achieved as compared to a non-oscillating nozzle wherein the subsequent spray zones are attempted to be laid immediately next to each other.

[0078] The nozzle (252) is selected to provide a spray of fluid having a suitable spray pattern. The nozzle may create a constant spray pattern across the projected spray area. However, it has been found that by oscillating the nozzle, the fluid distribution across the spray pattern can be varied and by overlapping subsequent spray patterns, a more even coating is achieved. The oscillation may be a swinging motion wherein the amount of fluid emitted at the centre of an oscillation is caused to be greater than the amount of fluid emitted towards the extremes of oscillation. As explained, suitably there is a partial overlap of the spray areas after an initial traverse of the nozzle with subsequent relative movement of the fabric and a further traverse of the nozzle. Consequently as the fluid emitted towards the extremes comprises an overlap of two successive traverses a more even distribution of the fluid onto the fabric may be effected.

[0079] Typically, the traverse is envisaged as moving in a linear direction across the fabric. When integrated with an incremental movement of fabric through an ink jet printer, the traverse would be substantially perpendicular to the lengthwise incremental movement of the fabric. Here, the nozzle is mounted on an arm or other movement means that moves a nozzle mount. However the direction of the traverse may be at an angle to the perpendicular of the length of the fabric as shown in FIG. 13, for instance. Alternatively the movement means moves the nozzle mount simultaneously in a two axis, such as the length and with axis of the fabric so that the nozzle moves in a non-linear direction.

[0080] There may be two nozzles (256, 258) each of which is able to partially traverse a length of fabric, whilst simultaneously oscillating so that fluid is oscillated unevenly across the spray zone in the oscillating direction. The two nozzles may be arranged spaced in an oscillating direction so that two overlapping spray zones are deposited in a single traverse. Here the two nozzles may be mounted on a commonnozzle mount. Alternatively, the nozzles may be arranged in line so that fluid is sprayed at a common region (260) with the traverse of one nozzle coating to one side from the common region and the traverse of the other nozzle coating to the other side. Alternatively, each nozzle of the plurality of nozzles may be arranged to coat a first respective spray zone and then to move relative to the fabric. In this instance, the nozzles are mechanically arranged to move. Subsequent to the movement, each nozzle is arranged to coat a second respective spray zone adjacent and at least partially overlapping the respective first spray zone corresponding to that nozzle. Further spray zones may be created. After which the fabric is arranged to move relative to the nozzles, Here, the first nozzle coats in two or more successive spray zones a first area, and the second and each subsequent nozzle creates a second spray area of at least first and second spray zones. The increments being such that the first and second spray areas overlap. And the fabric incrementally moves to provide an uncoated area under each spray nozzle.

[0081] As envisaged above, the multiple inline nozzles may combine to lay a linear spray zone, or, as shown in FIG. 13, the plurality of nozzles may form an inclusive angle (262) of the traverse (264) of less than 180. The angle (262) may be more than 10 or more than 20 or more than 30 or more than 40 or less than 70 or less than 60 or less than 50. Only one nozzle (256, 258) at a time may effect a print at the common region. Moreover, one, or more than one nozzle may move in both directions of traverse and the fabric may be moved relative to the or each nozzle after laying a coating in one direction of traverse before effecting coating in the reverse direction.

[0082] The traverse may be in a direction perpendicular to the length of the fabric over at least part of the extent of the traverse. The apparatus is suitably controllable so that the rate of traverse and rate of fluid egress from the nozzles is controllable and customisable to the fabric and fluid being coated. For instance, the method may comprise varying the amount of fluid being emitted during different parts of the oscillation. Also, the method may comprise varying the extent of the oscillation. Suitably, the method may comprise causing the extent of the swinging oscillation to be more than 5 or more than 10 or more than 20 or less than 60 or less than 50 or less than 40. However, an oscillation having an angular movement of between 5 and 10 has been found to work well. Furthermore, the frequency of oscillation may be varied. The frequency oscillation may be between 1 Hz and 100 Hz, but a frequency of between 25 Hz and 40 Hz and in particular around 32 Hz has been found to work well. The speed of movement in the traverse direction may be varied. The rate that fluid is emitted may be varied. The distance between the fabric and the fluid nozzle may be varied.

[0083] It is envisaged the oscillation of the nozzles is achieved using a number of known techniques. For instance, each nozzle may be mounted to a nozzle mount via a pivot. A directly controlled motor could then be used to turn the nozzle to rotate through an angle to achieve the oscillation. However, preferably a periodic oscillation is required wherein the rate of angular movement has a sinusoidal function. With high precision, this is achievable with a directly controlled motor, but it has been found a more achievable system is to mechanically mount the nozzle to rotate about a pivot point through a mechanical coupling. For instance, as shown in FIG. 12 a carriage (270) may carry the nozzle and thus cause the nozzle to effect the traverse.

[0084] The carriage (270) includes an endless belt (272) looped around opposed wheels (274, 276) at least one of which is driven. The belt supports the nozzle 250 by two wheels (278, 280) that rest on the upper surface which wheels travel with the belt as the belt moves and guide the belt to drive a driving wheel 282.

[0085] The driving wheel (282), located between the wheels (278 and 280) bears against the underside of the belt and the linear direction of the belt may be deformed slightly or the belt extends under the wheels (278, 280) and over the driving wheel (282). The driving wheel (282) frictionally engages with the belt and is caused to rotate as the belt moves.

[0086] The nozzle (250) is mounted on a pivot (284). A reciprocating lever (286) is connected to the nozzle at a location spaced from the pivot (284). The lever (280) is mounted about a pivot (288). A further lever (290) is pivotally connected to the reciprocating lever as a pivot (292) spaced from the pivot (288). The further lever (290) is also connected to the driving wheel (282) at a pivot (294), radially spaced from the axis (296) of the driving wheel (282).

[0087] As the driving wheel rotates the pivot (294) moves up and down to cause the further lever (290) to move up and down. This in turn causes the lever (286) to move up and down at the pivot (292) thus causing the nozzle to oscillate.

[0088] In an alternative arrangement a motor may be directly or indirectly connected to the pivot (284) of the fluid nozzle to effect the oscillation thereof. The motor may drive the fluid nozzle in alternative directions. Thus the motor may be controlled to vary the extent of oscillation.

[0089] A controller (not shown) may control any one or more of the extent of oscillation, the frequency of oscillation, the speed of the traverse, the rate that fluid is emitted or the distance between the fluid nozzles and the fabric.

[0090] It will be appreciated that the oscillation means can be achieved in a number of ways so that the nozzle tilts about an axis, typically a horizontal axis so as to divert the spray at varying angles to the vertical and therefore achieve the uneven distribution across the spay zone.

[0091] Referring to FIG. 14, a second configuration of the nozzle is shown. It will be appreciated that the machine may be configured to swap between previous swinging configuration and the second configuration and that this is particularly achievable by mounting the nozzle to the shaft of a stepper motor that can be directly controlled to rotate through angular movements.

[0092] As shown in FIG. 14, the nozzle 350 is mounted to the shaft of a motor 360. Here the motor can operate in the first configuration by swinging about a centre of oscillation, for instance the centre of oscillation is substantially vertical. Alternatively, in the second configuration, the motor rotates the nozzle to be arranged with a principal direction angled to the vertical. In FIG. 14, the principal direction is indicated by arrow 351 and is the main direction that fluid is emitted from the centre of the nozzle. The angle to the vertical is shown as angle . Suitably the angle is around 45o. However, alternative angles are envisaged based on optimisation for the fluid and fabric.

[0093] The angling of the nozzle, causes the spray distribution to become uneven. In FIG. 14, the two extents of the spray pattern are indicated by lines 353 and 352. Due to the gravitational effects the spray distribution of the coating is caused to be heaviest nearest the nozzle at extent 353 and lightest furthest from the nozzle at extent 352. It has been further found that by oscillating the nozzle through short angular turns, the vibration causes the droplet pattern from the nozzle to be disturbed and therefore reduce localised hotspots within the spray pattern density. Advantageously, by coating the substrate unevenly and overlapping subsequent spray zones, a more even coating can be achieved.

[0094] FIG. 15 shows a further configuration of the oscillation arrangement to cause the fluid nozzle 450 to oscillate, Here, a bobbin 416 is arranged in an electromagnetic system 410 that acts on the bobbin 416 to cause the bobbin to move in a side-to-side oscillating arrangement. As will be appreciated, due to the bobbin being connected at an offset pivot point (as described below) the side-to-side movement might not be a pure lateral movement, but rather a part of an arc. As shown in FIG. 15, the electromagnetic system comprises first 412 and second 414 electromagnets. Here the bobbin 416 is a fixed magnet. Consequently, by turning the respective first and second electromagnets on and off, the bobbin can be urged towards each electromagnet. By appropriate timing, the bobbin is caused to oscillate back and forth between the electromagnets. Importantly, a dwell or delay at the change in movement can be reduced by appropriate control of the timing. A yoke arm 418 connects the bobbin 416 to the fluid nozzle 450. The fluid nozzle is arranged to pivot about a pivot point 460. Suitably, the pivot is a vibration mount that resists movement by urging the nozzle back to the datum. For instance, the vibration mount is suitably a resilient material able to twist. One end of the material is fixed to the nozzle and the other end fixed to an anchor. The nozzle rotates by twisting the material. The natural resiliency of the material urges the nozzle back to the datum. The vibration mount can therefore combine with the electromagnetic forces to smooth the movement and reduce dwell or delay at the directional change.

[0095] Once the fabric (10) has been treated, the fabric (10) is intermittently fed to a drying station (50) as shown in FIG. 3. The drying station includes means for applying heat energy. In some examples, using an emitter supported by a drying support. Suitably, the emitter comprises a heating element. Conveniently, the emitter comprises a reflective backing.

[0096] In some examples, the emitter is chosen and tuned to emit radiation of certain range of wavelengths. Conveniently, the range is suitably chosen for the fabric and coating to be dried. In some examples, the emitter is arranged to emit predominantly a narrow range of wavelengths. In one example, the emitter is arranged to emit close to a single wavelength.

[0097] For example, for drying fabric, and preferably cotton, a wavelength of more than 1.3 m (micrometres) is chosen. Preferably, a wavelength of 1.38 m is selected. Conveniently, for drying cotton a colour temperature in a range of 2000-2200 K (Kelvin) is chosen. In some examples, the colour temperature is 2100 K.

[0098] In some examples, the emitter comprises a highly reflective backplate to increase the efficiency of the transfer of energy to the fabric. Additionally or alternatively, a highly reflective plate may be placed opposite to the emitter in a direction of emission such that, in use, fabric is located between the emitter and the highly reflective plate. Conveniently, the highly reflective plate is arranged to reflect emitted energy. Suitably, emitted energy which has passed the fabric may thereby be redirected towards the fabric.

[0099] In some examples, the drying station comprises means for transferring mass from the fabric during the drying process. Conveniently, the drying station is configured to remove fluid, preferably moisture, resulting from the drying process.

[0100] Conveniently, the amount of heat energy emitted by a drying head of the drying station is chosen for quickly drying the fabric and removing any resulting vapour. In some examples, such may be achieved within a few seconds per square meter and, in one example, one second per square meter.

[0101] In this example, the drying station, which is more clearly shown in FIGS. 11a and 11b, comprises a moveable infrared drier (52). When in the drying position, a length of fabric (10) placed between the infrared drier (52) and a heat shield (54), such as a reflector, is heated by the thermal energy transferred by the infrared radiation. The region of thermal energy emitted from the infrared drier (52) is the drying zone. The proximity of the infrared drier (52) to the fabric can be varied in order to affect the speed of drying and/or heating. For example, a distance of between 100-200 mm can be used when the infrared drier (52) is static or a closer distance of between 25-100 mm, or preferably 10-50 mm, can be used when there is relative movement between the infrared drier (52) are the fabric (i.e. the infrared driver (52) is continuously moving). This allows the infrared drier to be close to the surface of the fabric (10) to be dried and/or heated. Advantageously, the use of an infrared drier (52) allows the drying means to be turned on and off as required because the infrared drier (52) can warm up quickly without detrimental performance effects. Furthermore, the drying zone can be well controlled. For example, the speed of the drier (52) relative to the fabric (10) can be varied as well as the distance between the drier (52) and the fabric (10).

[0102] A moveable arm (56) connected to the infrared drier (52) is configured to move relative to the fabric (10) when the fabric (10) is held in position. For example, the infrared drier (52) may move towards or away from the fabric (10) in a first direction (El) and side-to-side in a second direction (E2), substantially orthogonal to the first direction (E1). The infrared drier (52) may move beyond the edges of the fabric (10). This helps to evenly spread the distribution of heat and avoid scorching of the fabric (10). The sideways movement of the infrared heater (52), i.e. in the second direction, is preferably timed according to the movement of the dancing roller (30) and the spraying of the fabric (10). Therefore the fabric can be held in position in a stop-start nature to allow sections of the fabric (10) to be acted on at once. Alternatively, or additionally, the drier (52) may rotate away from the fabric (10) such that the drying rate of the fabric (10) is reduced even if the drier (52) remains on. Additionally, air movement over the fabric (10) may be used by blowing or suction force in order to encourage the removal of fluid particles from the fabric (10). Additionally, or alternatively, the infrared drier (52) may move in an up and down direction, i.e. a third direction, which is substantially orthogonal to the first and second directions. This ads further configurability depending on the type of drying required.

[0103] After the drying station (50), the fabric is sent through a printing station, which may be a separate station. When an inkjet printer is used (not shown), the printing nozzles acting on the fabric (10) move across the fabric (10) in a side-to-side motion. During the sideways movement of the nozzles, the fabric (10) is held substantially stationary in order to allow the ink to be passed onto the fabric (10) in a linear fashion. An array of nozzles arranged in a column (i.e. along the fabric (10)) may be used in order to concurrently move across the fabric (10) and act on a larger surface area. This allows a row of the fabric (10) to be printed on at once (as determined by the dancing roller (30)) before being moved out of the way by the next row of unprinted fabric (10). Advantageously, the continuous motion of the cleaning station (20) does not disrupt the stop-start motion required by the printing station (60).

[0104] FIGS. 5 and 6 show the front and back views of the apparatus, respectively. Typically, the rollers (12) are elongate to reduce inertial load and accommodate fabric (10) that may be at least 3m in width. The rollers (12) each has a rotation axis which may be powered or unpowered. Therefore, some rollers (12) may be used to drive the fabric (10) forward or may freewheel such that they spin freely. The axes of the rollers (12) are shown attached to framework (14) that provides the structure of the apparatus (100).

[0105] FIG. 7 shows a flow diagram of the apparatus (100) as a whole. The apparatus (100) is configured to receive a roll of fabric (10) and input the fabric (10) as a continuous length. After the input stage (200), the fabric is continuously fed to a cleaning stage (210), where debris is removed from the fabric (10) from at least one side of the fabric (10). The continuous motion of the fabric (10) movement is then changed into intermittent motion. Therefore sections of the fabric (10) are then fed to a spraying stage (220), whereby the fabric (10) is coated from at least one side with a pre-treatment fluid. The amount of penetration is controlled in order to embed the fabric (10) accordingly. After the spraying stage (220), sections of the fabric (10) are intermittently fed to a drying station (230), where the fabric (10) is dried in and the pre-treatment fluid is retained by the fabric (10). This drying action may extend to a heating action in order to prepare the fabric (10) for printing by inkjet. Once exposed to a drier in the drying stage (230), the fabric (10) is fed to a printing stage (240), whereby the fabric (10) is printed on by ink. This allows graphics to be applied to the pre-treated and dried fabric (10) before being outputted (250) for delivery or storage.

[0106] Advantageously, the apparatus minimises changeover disruption so that a different pre-treatment chemical can be quickly and more conveniently changed. The extent of chemical penetration into the fabric can be controlled by the use of nozzles to provide a more flexible method of coating the fabric. The moveable drier and/or improved transient nature of the drier prevents the fabric being scorched and allows the drying process to be unaffected when stationary. The moveable drying and/or spraying zone allows the fabric to be held in position. In summary, the apparatus provides greater customisation and flexibility for improved efficiency and reduced downtime.

[0107] Whilst the parts of the system operate exemplarily together, each various part may also be used in isolation and provide benefits to known drying or coating systems. In particular, it has been found that the material treatment station can be used in isolation to provide advantages over known padding and stenter processes. For instance, it has been found that by spraying the treatment a lower amount of chemicals need to be used in the treatment. That is, in the padding and stenter process, the fabric absorbs more treatment fluid than it needs, Whereas by spraying a more controlled delivery process is achieved. As such, not only can the coating be completed with less chemicals, but because less chemicals are used, different chemicals can be used. Moreover, the padding and stenter process uses a relatively dilute treatment, for instance around 80% water. In contrast, a less dilute treatment fluid can be used in the spray treatment process herein described because the treatment process is more controlled. As such, it has been found that significant energy savings can be made due less energy being required to evaporate the water from the treatment from the substrate.

[0108] Advantageously the method of coating and the spray coating apparatus provides a more uniform distribution of fluid, particularly at the joins between successive spray zones. A further advantage is that the printing on the fabric is effected at a faster speed.

[0109] Although preferred embodiment(s) of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes may be made without departing from the scope of the invention as defined in the claims.