WO2002058857A1

WO2002058857A1 - Cleaning apparatus

Info

Publication number: WO2002058857A1
Application number: PCT/GB2002/000332
Authority: WO
Inventors: Graham Robert Thompson; Keith Stuart Munro; John Penman
Original assignee: Ksm International Limited
Priority date: 2001-01-25
Filing date: 2002-01-25
Publication date: 2002-08-01
Also published as: GB0101881D0

Abstract

An apparatus for cleaning substrates is provided, the apparatus comprising a plurality of tacky rollers (12) arranged to contact a substrate (14) to be cleaned, and rotatably mounted about a common support (18, 20). Above the rollers (12) is disposed a reel of tacky material (16), arranged to advance in a direction perpendicular to the direction of rotation of the rollers (12). The tacky rollers (12) are arranged to contact the substrate (14) to remove contaminants therefrom, before being rotated about the support (18, 20) to contact the tacky reel (16), which then cleans the rollers (12). The tacky reel (16) is periodically advanced to refresh the cleaning surface. Multiple tacky rollers (12) may be mounted adjacent one another, to allow cleaning of substrates of larger width than an individual roller (12).

Description

CLEANING APPARATUS

The present invention relates to an apparatus for cleaning substrates; in particular, but not exclusively, substrates such as panels or webs. A number of methods of cleaning substrates such as panels or webs are in use. Substrates which may be cleaned by such methods include, but are not limited to, films, papers, laminates, fabrics, glass, and the like. Cleaning of such substrates may be of use in many industries, including, but not limited to, converting and coating industries, graphics and printing industries, electronics manufacture, and other industries. One such cleaning method is to pass the substrate through a cleaning apparatus having a tacky roller (also often known as an elastomer roller, rubber roller, or ^xblue roller' , due to the normally accepted colour of the tacky surface used thereon) arranged to contact the substrate. Contaminants on the substrate adhere to the tacky roller, and are removed from the substrate. However, when in prolonged use the tacky roller may lose some of its tack as the roller becomes covered in removed contaminants. Thus, to refresh the roller, a cleaning surface is arranged to contact the tacky roller, the cleaning surface being of greater tack than the tacky surface. Contaminants are thus removed from the tacky roller and adhere to the cleaning surface; the tacky roller is then refreshed and may be reapplied to the substrate to be cleaned.

However, such apparatuses suffer from a number of disadvantages. A substrate may require several passes through the apparatus to clean it sufficiently to be reused. A conventional tacky roller arrangement cannot be easily adjusted to provide a greater contact area or roller speed with respect to the substrate. Further, the conventional arrangement of the cleaning surface is that of a roll of tacky material disposed above the tacky roller; the roll is advanced in a direction longitudinal to a direction of movement of the substrate- periodically to remove contaminants from the tacky roller, and to advance a fresh portion of cleaning material into contact with the tacky roller. However, the size of the apparatus, and thus the size and number of substrates which can be cleaned, is limited by the material used for the roll of tacky material: the paper conventionally used is produced only in standard sizes; and of course there is a physical limit to the width of paper roll which can be produced. It is among objects of embodiments of the present invention to obviate or alleviate these and other disadvantages of existing cleaning apparatuses.

According to a first aspect of the present invention there is provided an apparatus for cleaning a substrate, the apparatus comprising at least one first tacky surface for cleaning a substrate and a second tacky surface for cleaning the first tacky surface (s), wherein the second tacky surface is of greater tack than the first tacky surface, and has a direction of motion substantially lateral to a direction of motion of the first tacky surface (s) .

In a preferred form, the apparatus comprises the first tacky surface for contacting a surface of a substrate, moving means for moving the first tacky surface and a substrate relative to one another, the second tacky surface for contacting the first tacky surface, the second tacky surface being of greater tack than the first tacky surface and a portion of the second tacky surface being selectively engageable with a portion of the first tacky surface, wherein the second tacky surface extends laterally of the first tacky surface, and the apparatus further comprises means for advancing a portion of the second tacky surface laterally to allow engagement of a further portion of the second tacky surface with the first tacky surface.

Thus, rather than extending in the direction of movement of the substrate, as does a conventional second tacky surface, the present invention is provided with a second tacky surface being perpendicular to the direction of movement of the substrate, or laterally of the first tacky surface. This allows the second tacky surface to engage with a first tacky surface of essentially any width, since the second surface need only be made longer rather than wider.

Preferably the first tacky surface is provided on a roller. The first tacky surface may conveniently be provided as a plurality of tacky surfaces, provided on a corresponding plurality of rollers . Each of the rollers is preferably selectively engageable with each of a substrate and the second tacky surface. The rollers may conveniently be movable about a support to locate each roller adjacent a substrate or adjacent the second tacky surface.

A plurality of first tacky surfaces may be provided laterally displaced with respect to one another; this allows one or more tacky surfaces to be assembled or 'ganged' to provide a greater available cleaning width without requiring specially-made wider tacky surfaces to be produced. Preferably the second tacky surface comprises a roll of tacky material . Conveniently the means for advancing the second tacky surface comprises motor means for advancing the roll. Preferably the direction of advance of the roll is substantially perpendicular to the direction of roll of the first tacky surface rollers. Preferably the width of the roll of tacky material is substantially equivalent to the length of the first tacky surface; thus, only enough tacky material is used to allow contact of the full area of the first tacky surface.

Preferably the apparatus further comprises means for disengaging the second tacky surface from the first tacky surface. Thus, the second tacky surface may be removed from all contact with the first tacky surface . Conveniently the disengaging means comprises means for altering the relative separation of the two tacky surfaces . The means for advancing the second tacky surface is preferably operably linked to the disengaging means, such that the second tacky surface will be advanced only when the second surface is disengaged from the first.

The apparatus may further comprise means for actuating the advancement means after the substrate has moved a predetermined distance; this will allow the apparatus to be used such that the second tacky surface is advanced at times predetermined to maintain the cleaning efficiency of the first tacky surface.

According to a second aspect of the present invention, there is provided an apparatus for cleaning a substrate, the apparatus comprising a plurality of tacky surfaces for contacting a substrate surface, an endless drive member carrying the plurality of tacky surfaces, and means for moving the tacky surfaces and a substrate relative to one another, a second tacky surface for contacting the plurality of tacky surfaces, the second tacky surface being of greater tack than the plurality of tacky surfaces, and each of the plurality of tacky surfaces being selectively engageable with each of a substrate surface and the second tacky surface .

Thus, the apparatus of the present invention allows a number of primary tacky surfaces to be used, enabling some to be in contact with the substrate to remove contaminants, and the remainder of the tacky surfaces to be in contact with the second tacky surface, to clean the primary tacky surfaces. The apparatus may thus be used continuously for periods of time without requiring to be stopped and cleaned. Further, the use of a number of primary tacky surfaces allows more surfaces to be in contact with the substrate at once, so providing for greater cleaning power.

Preferably at least part of the moving means is arranged to move a substrate . Conveniently the moving means comprises a plurality of rollers which in use engage and move a substrate .

Preferably the plurality of tacky surfaces are provided on a corresponding plurality of rollers. These rollers may in use be run either with the movement of the substrate, or against the movement of the substrate; these options will provide for different cleaning speeds and efficiencies, so allowing more flexibility in the use of the apparatus .

Preferably the apparatus further comprises urging means for urging the plurality of tacky surfaces against a substrate . Conveniently the urging means may comprise a spring or the like.

Preferably the plurality of rollers are movable about a support, to locate each of said rollers adjacent a substrate or adjacent said second tacky surface. Preferably the apparatus further comprises means for moving the plurality of rollers about a support. The support may be common to all of the rollers, or there may be individual supports for each roller or for a group of rollers. Preferably the endless drive member comprises a flexible member, for example a chain, belt, or the like. Preferably the apparatus comprises a chain drive or the like and motor means for moving the rollers about a support; the support may conveniently comprise a wheel or wheels on which the chain or the like is mounted. Alternatively, the rollers may be arranged on a common frame, the frame being rotatable about an axis. A further alternative comprises each roller arranged separately on a support, each support being pivotable about an axis .

Preferably the plurality of rollers are operably linked such that at all times at least one of said plurality of rollers is in contact with a substrate.

Preferably the second tacky surface is provided as a roll of tacky material. Preferably also the roll is advanceable to present a fresh portion of tacky surface to the plurality of tacky rollers. Conveniently the roll is advanceable in a direction substantially perpendicular to the direction of roll of the plurality of tacky rollers; this allows the use of a narrow width of second tacky material with primary rollers of essentially any width. Preferably the apparatus further comprises means for indexing the roll of tacky material . According to a further aspect of the present invention, there is provided an apparatus for cleaning a substrate, the apparatus comprising a plurality of tacky surfaces for contacting a substrate surface, means for moving the tacky surfaces and a substrate relative to one another, a second tacky surface for contacting the plurality of tacky surfaces, the second tacky surface being of greater tack than the plurality of tacky surfaces, and each of the plurality of tacky surfaces being selectively engageable with each of a substrate surface and the second tacky surface, wherein the apparatus does not have any means for varying air pressure adjacent the substrate.

These and other aspects of the present invention will now be described by way of example only and with reference to the accompanying Figures, in which :

Figure 1 shows a perspective view of a portion of an apparatus for cleaning substrates in accordance with a first aspect of the present invention;

Figure 2 shows a perspective view of a pair of ganged roller modules as may be used with the apparatus of Figure

1;

Figure 3 shows an alternative perspective view of the parts shown in Figure 2;

Figure 4 shows a perspective view of a portion of an apparatus for cleaning substrates in accordance with a second aspect of the present invention; and

Figure 5 shows a perspective view of a modified portion of the apparatus of Figure 4.

Referring first of all to Figure 1, this shows a perspective view of a portion of an apparatus 10 for cleaning substrates, in accordance with a first embodiment of the present invention. The apparatus 10 includes a number of primary tacky or "elastomer" rollers 12 arranged for contacting a substrate (such as a panel or a web) surface 14. The apparatus 10 also includes a number of rollers (not shown) located beneath the substrate surface 14, arranged to move the substrate 14 through the apparatus 10 in the direction indicated by arrow A. A second tacky surface 16 in the form of an adhesive roll is located above the primary tacky rollers 12. The adhesive roll 16 has a greater tack than the primary tacky rollers 12, such that contaminants on the primary rollers 12 will be transferred to the adhesive roll 16 when the two surfaces are in contact. The primary tacky rollers 12 are arranged as will be described below such that they may be moved around a cogwheel 18 and chain 20 arrangement, to bring a selected tacky roller 12 into contact with either the substrate surface 14 or the adhesive roll 16. Alternatively, the rollers 12 may be mounted on a common shaft which is itself rotatable about a central pivot. Each tacky roller 12 is rotatably mounted between first and second mounting members

40, which members 40 are themselves fixedly mounted on respective movable chains 20.

The adhesive roll 16 includes a first source roll 22 and a second takeup roll 24 located either side of the primary tacky rollers 12, with the source and takeup rolls 22, 24 capable of being rotated so as to advance a portion of the adhesive roll 16 onto the takeup roll 24. The adhesive roll 16 is advanced in the direction indicated by arrow B, substantially perpendicular to the direction of movement of the substrate surface 14, indicated by arrow A.

In use, the apparatus operates as follows. A contaminated substrate 14 is fed into the apparatus 10, and moved past the primary tacky rollers 12 in the direction of arrow A by a series of rollers (not shown) disposed beneath the substrate 14. The primary tacky rollers 12 are slowly moved about the path defined by the cogwheel 18 and chain 20 arrangement, such that at least one of the rollers 12 is , in contact with the substrate surface 14 at any time. As the substrate 14 is advanced through the apparatus 10, the tacky roller 12 in contact with the substrate 14 moves over a part of the substrate surface, and any contaminant on that part of the surface is transferred onto the tacky roller 12.

After a certain time, the tacky roller 12 in contact with the substrate 14 reaches the end of the lower portion of its path, and is moved to the upper portion of the path, where it contacts the adhesive roll 16. At this time, one of the tacky rollers 12 which has been in contact with the adhesive roll 16 moves to the lower portion of the path and into contact with the substrate 14. The time that each roller 12 is in contact with the substrate 14 is determined by the speed of rotation; variation of this speed and the speed of advance of the substrate 14 itself can affect the degree of cleaning applied to a particular substrate .

Once the tacky roller 12 is in contact with the adhesive roll 16, the roller 12 continues to advance, and moves across the surface of the adhesive roll 16, rotating as it goes. As the tacky roller 12 rotates, contaminants are transferred from the roller 12 to the adhesive roll 16, thereby cleaning the tacky roller 12 and preparing it for a second pass over the surface of the substrate 14. The width of the adhesive roll 16 may be selected to correspond to roughly the circumference of a tacky roller 12; thus, as the roller 12 reaches the edge of the adhesive roll 16, it will have undergone a complete rotation, and so be cleaned. The adhesive roll 16 may of course be selected to be wider than the circumference of the rollers 12, such that each roller will make more than one rotation across the surface of the adhesive roll 16.

As the cleaning process continues, the part of the adhesive roll 16 exposed to contact with the tacky rollers 12 will become contaminated itself, and unable to clean the tacky rollers 12 to the same degree of efficiency. Periodically, therefore, the adhesive roll 16 is lifted out of contact with the tacky rollers 12, by a mechanical linkage (not shown) to the source 22 and takeup 24 rolls, which rolls 22, 24 are then advanced to expose a fresh portion of the adhesive roll 16, and wind the contaminated portion onto the takeup roll 24. The rolls 22, 24 are then lowered once more to place the adhesive roll 16 back into contact with the tacky rollers 12. The frequency with which this is done may depend on the degree of contamination of the adhesive roll 16 (detected, for example, by an optical sensor) ; or may be performed as the tacky rollers 12 have rotated through a predetermined number of revolutions (detected, for example, through a simple mechanical linkage) .

As the period in which the adhesive roll 16 is out of contact with the tacky rollers 12 is relatively short, there is no need to stop the apparatus 10 while the adhesive roll 16 is advanced, since contamination may still be removed during this time. Further, the adhesive roll 16 need only be the width of the circumference of the rollers 12, and so can be produced to clean substrates of any width.

Figures 2 and 3 show perspective views of a portion 110 of a pair of ganged roller modules which may be used with the apparatus of Figure 1. The portion 110 is similar to that illustrated in Figure 1, with the exception that the primary tacky rollers 112 are arranged in two groups of three, each group of three being rotatable about a cogwheel 118 and chain 120 arrangement. As can be seen most clearly in Figure 3, the two groups of three rollers 112 are arranged to provide continuous longitudinal coverage. In this way, two or more tacky roller modules may be combined to allow cleaning of substrates of any width, in combination with the adhesive roll 116 arrangement described with reference to Figure 1.

Figures 4 and 5 show an alternative apparatus for cleaning substrates, in accordance with a further embodiment of the present invention. The arrangement of the tacky rollers 212 shown in these Figures is equivalent to that used in the apparatus of Figures 1 to 3. Three tacky rollers 212 are held pivotally on pairs of end blocks 240. The end blocks 240 are spring mounted on one of two chains 220 which extend around pairs of cogwheels 218. The cogwheels 218 are driven to rotate by a motor arrangement (not shown) , while the springs 242 serve to urge the rollers 212 outward against either the substrate 214 or an adhesive surface 216.

The adhesive surface 216 may take the form of either an adhesive plane (Figure 4) or an adhesive roll (Figure 5) , and differs from the arrangement of Figures 1 to 3 in that the direction of advance of the adhesive surface 216 is parallel to (rather than lateral to) the direction of rotation of the rollers 212. Although this arrangement does impose restrictions on the width of substrates which may be cleaned, the arrangement does allow continuous cleaning of the tacky rollers 212, since there is no need to separate the rollers 212 from the adhesive roll 216 in order to advance the roll 216.

In use, the cogwheels 218 are rotated as the substrate 214 is driven through the cleaning apparatus. This serves to advance one of the tacky rollers 212 over the surface of the substrate 214, so removing any contaminants thereon. When the roller 212 in contact with the substrate reaches the end of the chain path, the roller 212 moves round the path to contact the adhesive roll 216, while a fresh roller 212 contacts the substrate 214. At no point in the cycle are no rollers 212 in contact with the substrate 214. Those rollers 212 which are in contact with the adhesive roll 216 are cleaned of contaminant by virtue of the tackier surface of the adhesive roll 216, and so are able to pick up additional contaminant when coming back into contact with the substrate 214.

The rollers 212 may be controlled to advance around the chain path in either direction; the direction chosen will affect the cleaning properties of the apparatus, as will the speed of advance of the rollers 212.

It can be seen from the foregoing that the present invention provides an apparatus for cleaning substrates which is able to clean substrates of arbitrary width; and is able to clean and purge the tacky rollers while maintaining cleaning contact with the substrate to be cleaned. It will be understood that various modifications and alterations may be made to the apparatus described herein without departing from the scope of the invention. For example, instead of a chain and cogwheel drive, a number of tacky rollers may be commonly mounted on a solid frame structure or wheel which may itself be rotated. Alternatively, a number of rollers may be separately mounted on rotatable centres, and the rollers controlled individually to contact either the substrate or the adhesive roll.

Claims

1. An apparatus for cleaning a substrate, the apparatus comprising at least one first tacky surface for cleaning a substrate and a second tacky surface for cleaning the first tacky surface (s), wherein the second tacky surface is of greater tack than the first tacky surface, and has a direction of motion substantially lateral to a direction of motion of the first tacky surface (s) .

2. The apparatus of claim 1, wherein a portion of the second tacky surface is selectively engageable with a portion of the first tacky surface; and wherein the second tacky surface extends laterally of the first tacky surface; the apparatus further comprising means for advancing a portion of the second tacky surface laterally to allow engagement of a further portion of the second tacky surface with the first tacky surface.

3. The apparatus of claim 1 or claim 2, wherein the first tacky surface is provided on a roller.

4. The apparatus of claim 3, wherein the first tacky surface is provided as a plurality of tacky surfaces, provided on a corresponding plurality of rollers.

5. The apparatus of claim 4, wherein each of the rollers is selectively engageable with each of a substrate and the second tacky surface.

6. The apparatus of claim 5, wherein the rollers are movable about a support to locate each roller adjacent a substrate or adjacent the second tacky surface.

7. The apparatus of any preceding claim, wherein a plurality of first tacky surfaces are provided laterally displaced with respect to one another.

8. The apparatus of any preceding claim, wherein the second tacky surface comprises a roll of tacky material .

9. The apparatus of claim 8, wherein the direction of advance of the roll is substantially perpendicular to the direction of roll of the first tacky surface rollers.

10. The apparatus of claim 8 or 9 , wherein the width of the roll of tacky material is substantially equivalent to the length of the first tacky surface.

11. The apparatus of any preceding claim, further comprising means for disengaging the second tacky surface from the first tacky surface.

12. The apparatus of claim 11, wherein the disengaging means comprises means for altering the relative separation of the two tacky surfaces.

13. The apparatus of claim 2, further comprising means for actuating the advancement means after the substrate has moved a predetermined distance; this will allow the apparatus to be used such that the second tacky surface is advanced at times predetermined to maintain the cleaning efficiency of the first tacky surface.

14. An apparatus for cleaning a substrate, the apparatus comprising a plurality of tacky surfaces for contacting a substrate surface, an endless drive member carrying the plurality of tacky surfaces, and means for moving the tacky surfaces and a substrate relative to one another, a second tacky surface for contacting the plurality of tacky surfaces, the second tacky surface being of greater tack than the plurality of tacky surfaces, and each of the plurality of tacky surfaces being selectively engageable with each of a substrate surface and the second tacky surface .

15. An apparatus for cleaning a substrate, the apparatus comprising a plurality of tacky surfaces for contacting a substrate surface, means for moving the tacky surfaces and a substrate relative to one another, a second tacky surface for contacting the plurality of tacky surfaces, the second tacky surface being of greater tack than the plurality of tacky surfaces, and each of the plurality of tacky surfaces being selectively engageable with each of a substrate surface and the second tacky surface, wherein the apparatus does not have any means for varying air pressure adjacent the substrate.

16. The apparatus of claim 14 or 15, wherein the plurality of tacky surfaces are provided on a corresponding plurality of rollers .

17 . The apparatus of claim 16 , further comprising urging means for urging the plurality of tacky surfaces against a substrate .

18. The apparatus of claim 16 or 17, wherein the plurality of rollers are movable about a support, to locate each of said rollers adjacent a substrate or adjacent said second tacky surface.

19. The apparatus of claim 18, further comprising a chain drive or the like and motor means for moving the rollers about a support .

20. The apparatus of any of claims 16 to 19, wherein the plurality of rollers are operably linked such that at all times at least one of said plurality of rollers is in contact with a substrate.

21. The apparatus of any of claims 14 to 19, wherein the second tacky surface is provided as a roll of tacky material.

22. The apparatus of claim 21, wherein the roll is advanceable in a direction substantially perpendicular to the direction of roll of the plurality of tacky rollers.