GB2528052A

GB2528052A - Contact cleaning apparatus

Info

Publication number: GB2528052A
Application number: GB1412052.1A
Authority: GB
Inventors: Graham Thomson; Hunter Paterson
Original assignee: ITW Ltd
Current assignee: ITW Ltd
Priority date: 2014-07-07
Filing date: 2014-07-07
Publication date: 2016-01-13
Also published as: GB201412052D0

Abstract

A contact cleaning apparatus 1, for removing contaminants from the surface of a work piece 11, comprising at least one pair of opposing surfaces 5 having a nip 119 between, and a pressurised gas delivery device 3, located in advance of the opposing surfaces 5, to deliver a directed stream of pressurised gas to deflect the leading edge 25 of a work piece 11 into the nip 119. The pair of opposed surfaces may comprise a roller, preferably a cleaning roller 5, and a planar surface, such as a moving conveyer (509, fig 7), or a pair of rollers 5, at least one of which may be a cleaning roller 5. The gas delivery device preferably comprises a manifold having at least one, but preferably a plurality, of apertures (23, fig 4) or slots (323, fig 5). The gas delivery device further has a, or a plurality of, nozzles (22, fig 4) which may extend across the entire width of the apparatus; wherein the gas pressure emitted may be adjustable. The apparatus may also comprise at least one sensor to detect the proximity of a leading edge 25 of the work piece to the nip 119.

Description

Contact Cleaning Apparatus The present invention relates to contact cleaning apparatus, and particularly, but not exclusively, to contact cleaning apparatus employing a cleaning roller and an adhesive roller for removing contamination and/or debris from a curved flexible surface to be cleaned.

Contact cleaning is used to clean substrate surfaces. Once cleaned the substrate surfaces may be used in a variety of sophisticated processes such as in the manufacturing of electronics) photovoltaics and flat panel displays. Usually, a rubber or elastomeric cleaning roller is used to remove contaminating particles from a substrate surface and an adhesive roller can then be used to remove the contaminating particles from the cleaning roller. This allows the cleaning roller to maximise its efficiency in removing contaminating particles from the substrate surface. Such apparatus operates by providing the cleaning roller with a surface of relatively low tackiness that contacts an adhesive roller of relatively high tackiness, the respective rollers being arranged parallel to one another and contacting each other over substantially their entire length. As a web or sheet material (hereinafter referred to as a work piece] is conveyed over the surface of the cleaning roller, debris on the work piece is removed. In order that the cleaning roller remains effective over a period of time, the removed debris is transferred to, and retained by, the adhesive roller during rotation of the respective rollers. Commonly, the work piece to be cleaned is conveyed through the nip of at least two opposed rollers, at least one of which is a cleaning roller. If pairs of cleaning rollers are used, particulate material can be simultaneously removed from the opposing surfaces of the work piece.

As a work piece is conveyed in a direction of travel towards the nip of at least two opposed rollers in the cleaning apparatus, any curvature of the work piece out of a single plane including the surface of the work piece causes the leading edge of the work piece to hit one of the two opposed rollers rather than entering into the nip between them. In such cases, and particularly in high speed cleaning apparatus, such an event would require manual intervention to correctly align the leading edge of the work piece into the nip between the two opposed rollers. Time and productivity will be lost in such circumstances.

A similar issue will occur in the event that a single cleaning roller is used to clean a work piece conveyed on a moving belt or the like. In such arrangements, the work piece is conveyed towards the cleaning roller on the upper surface of a moving belt, such as a conveyor belt. As a work piece is conveyed in a direction of travel towards the nip between the cleaning roller and the moving belt in the cleaning apparatus, any curvature of the work piece out of a single plane including the surface of the work piece and upwards away from the upper surface of the moving belt causes the leading edge of the work piece to hit the cleaning roller rather than entering into the nip between the cleaning roller and the moving belt. In such cases, and particularly in high speed cleaning apparatus, such an event would require manual intervention to correctly align the leading edge of the work piece into the nip between cleaning roller and the moving belt. Time and productivity will also be lost in such circumstances.

The present invention aims to address these issues by providing a contact cleaning apparatus with at least one cleaning roller operable to remove contaminants from a surface of the work piece, the apparatus comprising at least one pair of opposing surfaces, the pair of opposing surfaces having a nip therebetween, and a pressurised gas delivery device, located in advance of the pair of opposing surfaces and operable to deliver a directed stream of pressurised gas sufficient to deflect the leading edge of a work piece into the nip between the pair of opposing surfaces.

In certain embodiments, the at east one pair of opposing surfaces is provided by at least one roller and an opposing substantially planar surface. More specifically, the substantially planar surface is a moving surface. Even more specifically, the substantially planar surface is a belt The belt may be a conveyor belt. In such arrangements) the work piece may be moved towards the nip between the roller and the opposing substantially planar surface on the upper surface of the substantially planar surface.

It is much preferred that the substantially planar surface travels in the same direction as the travel direction of the work piece through the contact cleaning apparatus.

It is much advantageous that the at least one roller is positioned above the substantially planar surface. In this way, a work piece can be conveyed through the apparatus on the moving surface and under the at least one roller.

In certain embodiments, the at least one roller is a cleaning roller.

In certain embodiments, the at least one pair of opposing surfaces comprises at least one pair of opposing rollers, the pair of opposing rollers having a nip therebetween, and a pressurised gas delivery device, located in advance of the pair of opposing rollers and operable to deliver a directed stream of pressurised gas sufficient to deflect the leading edge of a work piece into the nip between the pair of opposing rollers.

In embodiments of the invention, the at least one pair of opposing rollers may comprise the at least one cleaning roller. In certain embodiments, the pair of opposing rollers may comprise a pair of cleaning rollers.

In embodiments of the invention, the at least one pair of opposing surfaces are preferably located in advance of the at least one cleaning roller.

More specifically, the at least one pair of opposing rollers may be located in advance of the at least one cleaning roller.

The pair of opposing surfaces may be a pair of control rollers. In a contact cleaning system comprising a pair of control rollers, the control rollers are preferably located in advance of a further pair of opposing surfaces, at least one of the further pair of opposing surfaces being the at least one cleaning roller. In certain embodiments, the further pair of opposing surfaces may comprise two opposing cleaning rollers.

In alternative arrangements, the further pair of opposing surfaces may comprise a cleaning roller and an opposing substantially planar surface. More specifically, the substantially planar surface is a moving surface. Even more specifically, the substantially planar surface is a belt The belt may be a conveyor belt. In such arrangements) the work piece may be moved towards the nip between the roller and the opposing substantially planar surface on the upper surface of the substantially planar surface.

The contact cleaning apparatus may further comprise a third pair of opposing surfaces. The third pair of opposing surfaces are preferably located after the first and second pairs of opposing surfaces in the travel direction of the work piece through the apparatus. In certain embodiments, at least one of the third pair of opposing surfaces is a cleaning roller.

In certain embodiments, one of the third pair of opposing surfaces is a cleaning roller and the other is a substantially planar moving surface. In such embodiments, the substantially planar moving surface is located below the cleaning surface of the cleaning roller. In this way, the work piece can be conveyed on the moving surface as it travels through the apparatus.

In certain embodiments, the third pair of opposing surfaces comprises two opposing cleaning rollers.

The contact cleaning apparatus may further comprise a fourth pair of opposing surfaces. The fourth pair of opposing surfaces are preferably located after the first, second and third pairs of opposing surfaces in the travel direction of the work piece through the apparatus.

In certain embodiments, the fourth pair of opposing surfaces is a pair of control rollers.

In preferred embodiments, the sequence of the pairs of opposing surfaces taken in the direction of travel of a work piece through the nips between each of the pairs of surfaces is: first pair of opposing control rollers, second pair of opposing surfaces the second pair comprising the at least one cleaning roller, third pair of opposing surfaces and fourth pair of opposing control rollers.

In certain embodiments, the third pair of opposing surfaces comprises at least one further cleaning roller.

Each roller in the, or each, pair of opposing rollers comprises a shaft. The roller shaft is oriented transverse to the direction of travel of the work piece.

The, or each, pair of opposing rollers comprises a nip between the opposing rollers through which a work piece can travel.

The pressurised gas delivery device preferably comprises a manifold having at least one aperture therein. Pressurised gas can be delivered onto the surface of the work piece adjacent the leading edge of the work piece through the aperture in the manifold. In certain embodiments, the manifold comprises a plurality of apertures.

More specifically, the manifold comprises a plurality of apertures through which pressurised gas can be delivered onto the surface of the work piece adjacent the leading edge of the work piece. In such embodiments, jets of pressurised air are directed onto the surface of the work piece adjacent the leading edge of the work piece as the work piece travels towards the nip between the pair of opposing surfaces. In this way, any curvature in the work piece away from the nip of the opposing surfaces can be obviated by the jet(s) of air directed on the surface of the work piece proximate the leading edge, causing the leading edge of the work piece to align with the nip between the opposing surfaces.

The manifold may, alternatively, comprise a slot or slots through which a curtain or curtains of pressurised gas can be delivered to the leading edge of the work piece.

In embodiments wherein the manifold comprises one or more slots as opposed to apertures, in should be understood that the manifold will require a higher input gas pressure to cause the required deflection in the leading edge of the work piece than is the case when the manifold comprises one or more apertures.

In certain embodiments, the manifold comprises a pipe.

In alternative embodiments, the pressurised gas delivery device may comprise at least one nozzle. The pressurised gas delivery device may comprise a plurality of nozzles. The or each nozzle is preferably oriented to direct pressurised gas onto the surface of the work piece proximate the leading edge, causing the leading edge of the work piece to align with the nip between the opposing surfaces. The nozzle(s) is operable to deliver a jet of pressurised gas onto the surface of the work piece proximate the leading edge.

The jet(s) or curtain(s) of pressurised gas may be delivered in pulses or as a constant flow of gas. It is preferred that the gas is delivered in pulses. It is much by preference that the pulses are timed to coincide with the leading edge of the work piece being located adjacent the nip between the pair of opposing surfaces. In embodiments wherein the work piece is comprised of discreet sheets of material, the time delay between pulses of delivered gas will be such as to deliver a pulse of gas to the surface of each discreet sheet of material adjacent the leading edge of the material. In this way) each leading edge of material will be aligned with the nip of the pair of opposing surfaces by virtue of the directed pulse of gas deflecting the leading edge of each sheet of material into the nip of the pair of opposing surfaces.

The pressurised gas delivery device is preferably fluidly connected to a pressurised gas source. Preferably, the pressurised gas source is a canister or bottle.

Alternatively, the pressurised gas source maybe a continuous gas source.

The pressurised gas may be an inert gas or mixture of gases. Preferably the gas is air, nitrogen, argon or similar. In preferred embodiments, the gas is air.

The pressurised gas delivery device preferably extends transversely to the direction of the work piece through the apparatus. More specifically, in embodiments comprising a pair of opposing rollers, the pressurised gas delivery device preferably extends in a direction parallel to the longitudinal axis of each of the pair of opposing rollers.

The pressurised gas delivery device preferably extends across substantially the entire width of the apparatus.

The pressurised gas delivery device preferably extends across substantially the entire width of the work piece.

The pressure of the gas exiting the pressurised gas delivery device towards the work piece is preferably adjustable. The pressure of gas is preferably adjustable to be sufficient to deflect the leading edge of the work piece into the nip between the pair of opposing surfaces. The more rigid the material of the curved work piece, the greater the gas pressure that will be required to deflect the curvature of the work piece into the nip between the pair of opposing rollers.

The contact cleaning system may further comprise at least one sensor located and operable to detect the proximity of a leading edge of a work piece to the nip between the pair of opposing surfaces.

In preferred embodiments, when the sensor detects the leading edge of a work piece as being proximate the nip between the pair of opposing surfaces, pressurised gas is delivered onto the surface of the work piece adjacent the leading edge of the work piece so as to align same with the nip between the pair of opposing surfaces.

In certain embodiments, the apparatus may further comprise a control system operably linked to the sensor. The control system is preferably responsive to input signals from the sensor and operable to provide an activation signal to the pressurised gas delivery gas. The activation signal preferably causes pressurised gas to be delivered from the pressurised gas delivery device.

The work piece is preferably a curved substrate. More specifically, the curved substrate may be a curved flexible material. Even more specifically, the curved flexible material maybe sheet of material. The sheet may be formed of a copper foil or a plastic foil or film. The film or foil thickness will typically be around 50 microns thickness. The curvature in the sheet material may be caused by the sheet being prone to curvature out of the plane including the upper surface of the sheet.

The work piece may be a continuous sheet of material. Alternatively, the work piece may comprise discreet sheets of material. Each discreet sheet will comprise a leading edge and a trailing edge. In such embodiments, the pressurised gas is preferably directed onto the surface of each sheet at a location proximate the leading edge of each sheet.

The work piece may be a substantially planar material.

The substantially planar material may be a panel of material. The panel may be prone to curvature out of the plane including the upper surface of the panel. The panel may be formed from a flexible material prone to curvature at a leading edge.

In the programmable control board (PCBJ industry, for example, a panel may be a planar, flexible material such as a film or the like, and may be of any desired thickness.

The contact cleaning apparatus may further comprise an inbound conveyor. The inbound conveyor is preferably oriented to support the work piece before the work piece is delivered to the nip between the pair of opposing surfaces.

In certain arrangements, the inbound conveyor may form one of the pair of opposing surfaces.

More specifically, the inbound conveyor supports the work piece and is operable to move same in a travel direction towards the nip between the pair of opposing surfaces. Even more specifically, the inbound conveyor supports the work piece and is operable to move same in a travel direction towards the nip between the foremost pair of opposing surfaces.

The contact cleaning apparatus may further comprise an outbound conveyor. The outbound conveyor is preferably oriented to support the work piece after the work piece has passed through the nip between the pair of opposing surfaces. More specifically, the outbound conveyor supports the work piece and is operable to move same in a travel direction after the work piece has passed through the nip between the pair of opposing surfaces. Even more specifically, the outbound conveyor supports the work piece and is operable to move same in a travel direction away from the nip between the lattermost pair of opposing surfaces.

In certain arrangements, the inbound conveyor and the outbound conveyor may be one and the same.

The contact cleaning apparatus may be a sheet to sheet contact cleaning machine.

When the contact cleaning apparatus is a sheet to sheet contact cleaning machine, the work piece delivered to the nip between the opposing surfaces is a sheet of material and the work piece fed away from the nip between the opposing surfaces is that same sheet of material. The sheet of material will undergo a contact cleaning process through at least one pair of opposing surfaces comprising a cleaning roller in the contact cleaning apparatus.

The contact cleaning apparatus preferably comprises at least one adhesive roller. It is much by preference that the surface of the adhesive roller contacts the surface of the at least one cleaning roller. The adhesive rofler being operable to remove contaminants from the surface of the at least one cleaning roller.

The contact cleaning apparatus may comprise at least two adhesive rollers. It is much by preference that the surface of each adhesive roller contacts the surface of at least one cleaning roller. The adhesive rollers being operable to remove contaminants from the surface of the cleaning roller with which it is in contact.

The present invention will now be described by way of example only, and with reference to the accompanying drawings, in which: Figure la and lb are a schematic side view of a contact cleaning apparatus employing a pressurised gas delivery device and a pair of control rollers in accordance with embodiments of the present invention; Figure 2a and 2b are a schematic side view of a contact cleaning apparatus employing a pressurised gas delivery device in accordance with embodiments of the present invention; Figure 3 is a schematic side view of a contact cleaning apparatus employing a pressurised gas delivery device and an inbound and an outbound conveyor in accordance with embodiments of the present invention; Figure 4 is a schematic plan view of the underside of a pressurised gas delivery device for use in a contact cleaning apparatus in accordance with a first embodiment of the present invention; Figure 5 isa schematic p'an view of the underside of an alternative pressurised gas delivery device for use in a contact cleaning apparatus in accordance with a second embodiment of the present invention; Figure 6 is a schematic plan view of the underside of a yet further alternative pressurised gas delivery device for use in a contact cleaning apparatus in accordance with a second embodiment of the present invention; and Figure 7 is a schematic side view of an alternative contact cleaning apparatus of the invention comprising a pressurised gas delivery device and a pair of opposing surfaces comprising a substantially planar moving surface in accordance with embodiments of the present invention.

In the present invention it has been appreciated that a contact cleaning apparatus can be manufactured in a manner that allows a curved work piece to be delivered into the nip between two opposing surfaces during a contact cleaning process.

Contact cleaning apparatus can be provided with a pressurised gas delivery device to deflect the leading edge of a curved work piece into the apparatus. By using the pressurised gas to deflect the leading edge of the curved work piece into alignment with the opening of the contact cleaning apparatus, the work piece is less likely to jam on entry to the contact cleaning apparatus. This can be achieved by providing a pressurised gas delivery system, as described below.

Figure la is a schematic side view of a contact cleaning apparatus 1 employing a pressurised gas delivery device 3, which in the depicted embodiment is an air blade, in accordance with embodiments of the present invention. The contact cleaning apparatus 1 comprises two adjacent pairs of opposing contact cleaning rollers S and two adhesive rollers 7a, 7b mounted at the end of an inbound conveyor 9 on which a work piece 11 for cleaning is carried. The contact cleaning rollers 5 are elongate and generally cylindrical in shape, and is mounted on a holder (not shown) having an axis perpendicular to the plane of view about which the contact cleaning rollers S are free to rotate. The specific structure of the contact deaning rollers 5 is described in more detail below. The adhesive rollers 7a, 7b are generally cylindrical in shape, and comprises a body having a surface on which adhesive is present, and are each also mounted on a holder (not shown] having an axis perpendicular to the plane of view and parallel to that of the contact deaning rollers 5 about which the adhesive rollers 7a, 7b are free to rotate. The contact cleaning rollers 5 and adhesive rollers 7a, 7b are mounted in such a manner such that each of the contact cleaning rollers 5 is in contact with one of the adhesive rollers 7a, 7b such that clockwise rotational movement of the contact cleaning rollers 5 results in counter-clockwise rotational movement of the adhesive roller 7a, 7b with which it is in contact and vice versa. The need for the contact cleaning rollers 5 and adhesive rollers 7a, 7b to be in contact will be clear from the description of use below. The contact cleaning rollers S are also mounted so as to be able to be in contact with the surface of a work piece 11 to be cleaned as it passes on a conveyor 9.

It should be understood that in alternative embodiments, not shown, at least one of rollers 5 is a contact cleaning roller and each of the other rollers 5 may be a guide roller. In further embodiments, at least one of the rollers 5 in each opposing pair of rollers 5 is a contact cleaning roller and the other of the rollers in each pair of opposing rollers 5 maybe a guide roller.

In yet further embodiments, not shown, there may be provided only one pair of opposing rollers 5. In such an embodiment, one or both of the opposing rollers S may be a contact cleaning roller.

A pair of opposing control rollers 13a, 13b are positioned at the end of the inbound conveyor 9 and have a nip 19 between their surfaces and into which the work piece 11 will be fed.

Air blade 3 is located in advance of and above the nip 19 between the pair of control rollers 13a, 13b and above inbound conveyor 9. The air blade 3 is generally cylindrical in shape, and comprises a body having one or more apertures (see Figures 4, 5 and 6) therein a through which pressurised gas is directed in a direction B towards conveyor 9. The body of the air blade 3 is mounted on a holder [not shown) having an axis perpendicular to the plane of view and parallel to that of the contact cleaning rollers 5. The air blade 3 extends across substantially the entire width of conveyor 9 along an axis perpendicular to the plane of view.

Guide rollers 15 and 17 may optionally be provided between the pair of controller rollers 13a, 13b and the last pair of opposing contact cleaning rollers 5 respectively.

The guide rollers 15 and 17 provide additional support for the work piece 11 as it travels through the apparatus 1. The guide rollers 15, 17 are generally cylindrical in shape, and are each also mounted on a holder [not shown) having an axis perpendicular to the plane of view and parallel to that of the contact cleaning rollers and the adhesive rollers 7a, 7b and are free to rotate.

A curved work piece 11 to be cleaned is processed as follows. A substrate 11 being a curved sheet or panel of material is positioned on the upper surface of an inbound conveyor 9, which in Figure 1 moves from right to left as indicated by arrow A. The substrate 11 to be cleaned passes underneath the contact air blade 3 which directs pressurised air in a direction indicated by arrow B towards the surface of the substrate 11 proximate its leading edge 25. The pressurised air directed onto the surface of the substrate 11 causes a deflection in the curved substrate 11 towards the surface of the inbound conveyor 9. The deflection in the curved substrate aligns the leading edge 25 of the substrate 11 with the nip 19 between the pair of opposing control rollers 13a, 13b as shown in Figure lb. The substrate is passed between the rotating control rollers iSa, 13b towards the first pair of opposing contact cleaning rollers 5. Before coming into contact with the contact cleaning rollers 5, the upper surface of the substrate ii is covered with debris requiring removal, such as dust.

The contact cleaning rollers 5 contact the upper and, in the depicted embodiment) also the lower surface of the substrate 11, removing the debris by means of an electrostatic removal mechanism, where the inherent polarity of the material used to form the contact cleaning rollers 5 attracts the debris and causes it to stick to the surface of the contact cleaning rollers 5. The relative attractive force between the surface of the contact cleaning rollers 5 and the debris is greater than that between the debris and the surface of the substrate 11, hence the debris is removed. In the depicted arrangement, the substrate passes through two pairs of contact cleaning rollers 5 as it travels in direction A through the apparatus. The now clean substrate 11 continues along the travel path to an outbound conveyor (see Figure 3). In order to clean the contact cleaning rollers 5, the adhesive rollers 7a and 7b, each rotating in a counter-clockwise direction as indicated by arrows C, each contact the surface of one of the contact cleaning rollers 5 in each opposing pair. At this point the adhesive force between the debris and the adhesive present on the surface of the adhesive rollers 7a, 7b is greater than the electrostatic force holding the debris onto the surface of the contact cleaning rollers 5, and the debris is removed. The contact cleaning rollers 5 then rotate to present a clean surface to the next substrate 11 to be cleaned.

Figures 2a and 2b show a schematic side view of a contact cleaning apparatus 100 employing a pressurised gas delivery device 3, which in the depicted embodiment is an air blade, in accordance with embodiments of the present invention. The depicted arrangement differs of the arrangement described in relation to Figure 1 in that the control rollers and the guide rollers are omitted.

The contact cleaning apparatus 100 comprises two adjacent pairs of opposing contact cleaning rollers 5 and two adhesive rollers 7a, 7b mounted at the end of an inbound conveyor 9 on which a work piece 11 for cleaning is carried. The contact cleaning rollers 5 are elongate and generally cylindrical in shape, and is mounted on a holder (not shown) having an axis perpendicular to the plane of view about which the contact cleaning rollers 5 are free to rotate. The specific structure of the contact cleaning rollers 5 is described in more detail below. The adhesive rollers 7a, 7b are generally cylindrical in shape, and comprises a body having a surface on which adhesive is present) and are each also mounted on a holder (not shown) having an axis perpendicubr to the plane of view and parallel to that of the contact cleaning rollers 5 about which the adhesive rollers 7a, 7b are free to rotate. The contact cleaning rollers 5 and adhesive rollers 7a, 7b are mounted in such a manner such that each of the contact cleaning rollers 5 is in contact with one of the adhesive rollers 7a, 7b such that clockwise rotational movement of the contact cleaning rollers S results in counter-clockwise rotational movement of the adhesive roller 7a, 7b with which it is in contact and vice versa. The need for the contact cleaning rollers 5 and adhesive rollers 7a, 7b to be in contact will be clear from the description of use below. The contact cleaning roflers 5 are also mounted so as to be able to be in contact with the surface of a work piece 11 to be cleaned as it passes on a conveyor 9.

In yet ftirther embodiments, not shown, the may be provided only one pair of opposing rollers 5. In such an embodiment, one or both of the opposing rollers S may be a contact cleaning roller.

A pair of opposing control rollers 13a, 13b are positioned at the end of the inbound conveyor 9 and have a nip 19 between there surfaces and into which the work piece 11 will be fed.

Air blade 3 is located in advance of and above the nip 119 between the first of two pairs of contact cleaning rollers S and above inbound conveyor 9. The air blade 3 is generally cylindrical in shape, and comprises a body having one or more apertures (see Figures 4, 5 and 6) therein through which pressurised gas is directed in a direction B towards conveyor 9. The body of the air blade 3 is mounted on a holder (not shown) having an axis perpendicular to the plane of view and parallel to that of the contact cleaning rollers S. The air blade 3 extends across substantially the entire width of conveyor 9 along an axis perpendicular to the plane of view.

A curved work piece 11 to be cleaned is processed as follows. A substrate 11 being a curved sheet or panel of material is positioned on the upper surface of an inbound conveyor 9, which in Figure 2 moves from right to left as indicated by arrow A. The substrate 11 to be cleaned passes underneath the contact air blade 3 which directs pressurised air in a direction indicated by arrow B towards the surface of the substrate 11 proximate its leading edge 25. The pressurised air directed onto the surface of the substrate 11 causes a deflection in the curved substrate 11 towards the surface of the inbound conveyor 9. The deflection in the curved substrate aligns the leading edge 25 of the substrate 11 with the nip 119 between the pair of opposing contact cleaning rollers 5 as shown in Figure 2b. The substrate is passed between the rotating contact cleaning rollers 5 towards the second pair of opposing contact cleaning rollers 5. Before coming into contact with the contact cleaning rollers 5, the upper surface of the substrate 11 is covered with debris requiring removal, such as dust. The contact cleaning rollers 5 contact the upper and, in the depicted embodiment, also the lower surface of the substrate 11, removing the debris by means of an electrostatic removal mechanism, where the inherent polarity of the material used to form the contact cleaning rollers 5 attracts the debris and causes it to stick to the surface of the contact cleaning rollers 5. The relative attractive force between the surface of the contact cleaning rollers 5 and the debris is greater than that between the debris and the surface of the substrate 11, hence the debris is removed. In the depicted arrangement, the substrate passes through two pairs of contact cleaning rollers 5 as it travels in direction A through the apparatus. The now clean substrate 11 continues along the travel path to an outbound conveyor 27. In order to clean the contact cleaning rollers 5, the adhesive rollers 7a and 7b, each rotating in a counter-clockwise direction as indicated by arrows C, each contact the surface of one of the contact cleaning rollers 5 in each opposing pair. At this point the adhesive force between the debris and the adhesive present on the surface of the adhesive rollers 7a, 7b is greater than the electrostatic force holding the debris onto the surface of the contact cleaning rollers 5, and the debris is removed. The contact cleaning rollers 5 then rotate to present a clean surface to the next substrate 11 to be cleaned.

As can readily be seen in Figure 3, as substrate 11 travels in direction A along inbound conveyor 9, the leading edge 25 of the substrate is curved out of the plane of the surface of the substrate 11. Such curvature maybe in the order of 30mm. As the curved substrate passes under the pressurised gas delivery device 3, pressurised gas is deliver from a pressurised gas source (not shown) through at least one aperture (not shown) in the pressurised gas delivery device 3 in a direction shown by arrow B. The pressurised gas causes a deflection in the leading edge of the substrate 11 to flatten the substrate into a planar configuration. The leading edge 25 of the substrate 11 is then aligned with the nip 119 between the first pair of contact cleaning rollers 5. The substrate 11 then passes, in travel direction A, between the first pair of opposing rollers 5 and on to the second pair of opposing contact cleaning rollers 5. Once cleaned by contact with the two pairs of opposing contact cleaning rollers 5, the cleaned substrate 11 moves in travel direction A onto the outbound conveyor 27.

The pressurised gas delivery device 3 may take a number of forms. In each of Figures 4, 5 and 6 alternative embodiments of the pressurised gas delivery device 3 are shown as follows.

In Figure 4, the pressurised gas delivery device 3 is an air bar formed of an elongate and generally cylindrical body portion 21. The body portion 21 forms a manif&d through which pressurised gas is delivered to apertures 23 through tapered nozzles 22 having a bore therethrough. The manifold is fluidly connected to a pressurised gas supply (not shown]. The size of the opening of apertures 23 may be varied and will control the pressure at which the gas is delivered to the surface of the substrate.

In certain embodiments) the aperture width is adjustable to allow an operator to adjust the delivered gas pressure at the nozzle 22.

The body portion 21 of the device 3 preferably extends across the entire width of the inbound conveyor. In this way, the spaced apart apertures 23 are located to deliver jets of pressurised gas across the entire width of a substrate 11 on the inbound conveyor 9.

In Figure 5, the pressurised gas delivery device 300 is an air bar formed of an elongate and generally cylindrical body portion 321. The body portion 321 forms a manifold through which pressurised gas is delivered to an aperture 323 in the form of an elongate slot in body portion 321. The manifold is fluidly connected to a pressurised gas supply (not shown). The dimensions of the slot opening 323 may be varied and will control the pressure at which the gas is delivered to the surface of the substrate.

The body portion 321 of the device 300 preferably extends across the entire width of the inbound conveyor. In this way, the elongate slot 323 is located to deliver a curtain or blade of pressurised gas across the entire width of a substrate 11 on the inbound conveyor 9.

In Figure 6, the pressurised gas delivery device 400 is an air bar formed of an elongate and generally cylindrical body portion 421. The body portion 421 forms a manifold through which pressurised gas is delivered to three spaced apart apertures 423 in the form of elongate slots in body portion 421. The manifold is fluidly connected to a pressurised gas supply (not shown). The dimensions of the slot openings 423 may be varied and will control the pressure at which the gas is delivered to the surface of the substrate.

The body portion 421 of the device 400 preferably extends across the entire width of the inbound conveyor. In this way, the elongate slots 423 are together located to deliver a plurality of curtains or blades of pressurised gas across the entire width of a substrate 11 on the inbound conveyor 9.

In use, the pressurised gas delivery device 3. 300, 400 is fluidly connected to a pressurised gas source. The gas may be any inert gas such as air, nitrogen, argon or the like. In preferred arrangements, the gas is air as this provides the cheapest gas supply source. The pressurised gas delivery device 3, 300, 400 may be manually operated to deliver a stream or a pulse of pressurised gas onto the curved substrate 11 on inbound conveyor 9. Alternatively, the pressurised gas delivery device 3, 300, 400 maybe automatically operated to deliver a stream or a pulse of pressurised gas to the curved substrate 11 on inbound conveyor 9. In an automated process, the apparatus may comprise a controller and a sensor to deliver activation signals to operate the pressurised gas delivery device 3, 300, 400 to deliver a directed stream or pulse of pressurised gas onto the curved substrate 11 on inbound conveyor 9.

In embodiments wherein a pulse or pulses of pressurised gas are delivered from the pressurised gas delivery device 3, 300, 400, the pulse(s) are preferably timed to ensure the pressurised gas is delivered onto the leading edge of a substrate passing under the pressurised gas delivery device 3, 300, 400.

Figure 7 is a schematic side view of an alternative contact cleaning apparatus 500 employing a pressurised gas delivery device 3, which in the depicted embodiment is an air blade, in accordance with embodiments of the present invention. Alternative air blade arrangements in accordance with the invention may also be used in such an arrangement as is depicted in Figure 7.

The contact cleaning apparatus 500 comprises a pair of opposing surfaces provided by the cleaning surface of contact cleaning roller Sand the upper surface of inbound conveyor 509. Adhesive rofler 7a is mounted so as to be in contact with the cleaning surface of cleaning roller 5. Contact cleaning roller S is ocated above the upper surface of inbound conveyor 509 and in contact therewith. A work piece 11 for cleaning is carried on inbound conveyor 509. The contact cleaning roller 5 is elongate and generally cylindrical in shape, and is mounted on a holder (not shown) having an axis perpendicular to the plane of view about which the contact cleaning roller S is free to rotate. The specific structure of the contact cleaning roller 5 is described in more detail below. The adhesive roller 7a is generally cylindrical in shape, and comprises a body having a surface on which adhesive is present) and is also mounted on a holder (not shown) having an axis perpendicular to the plane of view and parallel to that of the contact cleaning roller 5 about which the adhesive roller 7a is free to rotate. The contact cleaning roller 5 and adhesive roller 7a are mounted in such a manner such that the contact cleaning roller 5 is in contact with the adhesive surface of the adhesive rollers 7a such that clockwise rotational movement of the contact cleaning roller S results in counter-clockwise rotational movement of the adhesive roller 7a with which it is in contact and vice versa. The need for the contact cleaning roller 5 and adhesive roller 7a to be in contact will be clear from the description of use below. The contact cleaning roller 5 is also mounted so as to be able to be in contact with the surface of a work piece 11 to be cleaned as it passes into the nip between the opposing surfaces of the cleaning roller and the substantially planar moving conveyor 509.

Air blade 3 is located in advance of and above the nip 519 between the pair of opposing surfaces provided by the cleaning surface of contact cleaning roller 5 and the upper surface of the inbound conveyor 509. The air blade 3 is generally cylindrical in shape, and comprises a body having one or more apertures (see Figures 4, 5 and 6) therein through which pressurised gas is directed in a direction B towards conveyor 509. The body of the air blade 3 is mounted on a holder (not shown) having an axis perpendicular to the plane of view and parallel to that of the contact cleaning roller 5. The air blade 3 extends across substantially the entire width of conveyor 509 along an axis perpendicular to the plane of view.

A curved work piece 11 to be cleaned is processed as follows. A substrate 11 being a curved sheet or panel of material is positioned on the upper surface of an inbound conveyor 509, which in Figure 7 moves from right to left as indicated by arrow A. The substrate 11 to be cleaned passes underneath the contact air blade 3 which directs pressurised air in a direction indicated by arrow B towards the surface of the substrate 11 proximate its leading edge 25. The pressurised air directed onto the surface of the substrate 11 causes a deflection in the curved substrate 11 towards the surface of the inbound conveyor 509. The deflection in the curved substrate aligns the leading edge 25 of the substrate 11 with the nip 519 between the pair of opposing surface provided by contact cleaning roller 5 and the upper surface of the inbound conveyor 509 in the region of the cleaning roller 5. The substrate is passed between the rotating contact cleaning roller 5 and the opposing surface of the moving planar conveyor 509. Before coming into contact with the contact cleaning roller 5, the upper surface of the substrate 11 is covered with debris requiring removal, such as dust The contact cleaning roller 5 contacts the upper surface of the substrate 11, removing the debris by means of an electrostatic removal mechanism, where the inherent polarity of the material used to form the contact S cleaning roller 5 attracts the debris and causes it to stick to the surface of the contact cleaning roller 5. The relative attractive force between the surface of the contact cleaning roller S and the debris is greater than that between the debris and the surface of the substrate 11, hence the debris is removed. In the depicted arrangement, the substrate passes through a pairs of opposing surfaces being the surface of the contact cleaning roller S and the upper surface of the conveyor 509 as it travels in direction A through the apparatus. The now clean substrate 11 continues along the travel path to an outbound conveyor 527. In order to clean the contact cleaning roller 5, the adhesive roller 7a, rotating in a counter-clockwise direction as indicated by arrows C, contacts the surface of the contact cleaning roller 5. At this point the adhesive force between the debris and the adhesive present on the surface of the adhesive roller 7a is greater than the electrostatic force holding the debris onto the surface of the contact cleaning roller 5, and the debris is removed. The contact cleaning roller 5 then rotates to present a clean surface to the next substrate 11 to be cleaned.

These and other embodiments of the present invention will be apparent from the scope of the appended claims.

Claims

Claims 1. A contact cleaning apparatus with at least one cleaning roller operable to remove contaminants from a surface of the work piece, the apparatus comprising at least one pair of opposing surfaces, the pair of opposing surfaces having a nip therebetween, and a pressurised gas delivery device, located in advance of the pair of opposing surfaces and operable to deliver a directed stream of pressurised gas sufficient to deflect the leading edge of a work piece into the nip between the pair of opposing surfaces.
2. A contact cleaning apparatus according to claim 1, wherein the at least one pair of opposing surfaces is provided by at least one roller and an opposing substantially planar surface.
3. A contact cleaning apparatus according to claim 2, wherein the substantially planar surface is a moving surface.
4. A contact cleaning apparatus according to claim 2 or claim 3, wherein the at least one roller is a cleaning roller.
5. A contact cleaning apparatus according to claim 1, wherein the at least one pair of opposing surfaces comprises at least one pair of opposing rollers.
6. A contact cleaning apparatus according to claim 5, wherein the at least one pair of opposing rollers comprises the at least one cleaning roller.
7. A contact cleaning apparatus according to claim 5 or claim 6, wherein the pair of opposing rollers comprises a pair of cleaning rollers.
8. A contact cleaning apparatus according to any one of the preceding claims) wherein the pressurised gas delivery device comprises a manifold having at least one aperture therein.
9. A contact cleaning apparatus according to claim 8, wherein the manifoki comprises a plurality of apertures.
10. A contact cleaning apparatus according to any one of claims 1 to 7, wherein the pressurised gas delivery device comprises a manifold comprising one or more slots.
11. A contact cleaning apparatus according to any one of claims 8 to 10, wherein the manifold comprises a pipe.
12. A contact cleaning apparatus according to any one of the preceding claims) wherein the pressurised gas delivery device comprises at least one nozzle.
13. A contact cleaning apparatus according to claim 12, wherein the pressurised gas delivery device comprises a plurality of nozzles.
14. A contact cleaning apparatus according to any one of the preceding claims, wherein the pressurised gas delivery device extends across substantially the entire width of the apparatus.
15. A contact deaning apparatus according to any one of the preceding claims, wherein the pressure of the gas exiting the pressurised gas delivery device towards the work piece is adjustable.
16. A contact deaning apparatus according to any one of the preceding claims, further comprising at least one sensor located and operable to detect the proximity of a leading edge of a work piece to the nip between the pair of opposing surfaces.