Abstract:
A contact cleaning roller which may be axially flexed to conform to a non-planar substrate surface for removing particles therefrom. In a preferred embodiment, a flexible shaft is covered with a high-tack sleeve comprising polyurethane, silicone, adhesive tape, or any other similar high-tack material. The shaft is rotatably suspended at either end in bearings in a frame, allowing the roller to conform to a non-planar substrate surface requiring cleaning, for example, a cathode ray tube screen.

Description:
DESCRIPTION  
         [0001]    The present invention relates to apparatus for cleaning particulate contamination from the surfaces of substrates; more particularly to cleaning apparatus having a particle-attracting (“contact cleaning”) roller for transferring particulate contamination from a substrate surface to the surface of the roller; and most particularly, to such apparatus wherein the contact cleaning roller is axially flexible and is especially suited to cleaning particles from non-planar substrate surfaces.  
           [0002]    It is well known to convey a web substrate around a cylindrical particle-attracting roller to cause particulate contaminants on the surface of the web substrate to be transferred to the surface of the roller, thereby cleaning the web substrate surface. Such rollers are known in the art as “contact cleaning rollers” (CCR&#39;s), and may be provided with a tacky surface comprising, for example, adhesive tape as disclosed in U.S. Pat. No. 4,009,047, or an electrostatically-active polymeric surface, for example, a polyurethane as disclosed in U.S. Pat. Nos. 5,611,281 and 5,699,738, or a silicone, which patents are herein incorporated by reference.  
           [0003]    Contact cleaning rollers in accordance with the prior art are suitable for cleaning surfaces of only planar substrates, such as plastic or other webs supported on rollers, or rigid sheet stock such as circuit boards. Slight surface irregularities may be accommodated in some applications by the compressibility of the polymeric sleeve, but more highly curved or non-planar surfaces cannot be cleaned readily by such rollers.  
           [0004]    It is a principal object of the invention to provide improved contact cleaning apparatus which can clean particles from non-planar substrate surfaces.  
           [0005]    Briefly described, a flexible contact cleaning roller in accordance with the invention is a flexible cylinder having an axis of rotation. The roller is formed of such material and in such a way as to permit the cylindrical shape to be deformed axially in response to radial force exerted on a surface of the roller as the roller is rolled along a substrate surface to be cleaned. Such forces may be applied randomly or non-randomly when such a roller is rolled along a non-planar surface. Such deformation permits the cleaning surface of the roller to remain in contact with the non-planar surface over the entire length of the roller as it is rolled along the surface to remove particles therefrom.  
           [0006]    Preferably, the roller comprises a flexible core, also referred to herein interchangeably as a shaft or mandrel, which may be formed of a flexible polymer, for example, nylon, or a flexible metal or other fatigue-resistant material, the core terminating in ends suitable for retention in sleeve or roller bearings at opposite ends thereof. A sleeve of high-tack material is formed over the core or mandrel, defining a tacky outer cleaning surface for removing particles from surfaces with which the cleaning surface comes into contact.  
           [0007]    Alternatively, the roller may comprise a substantially monolithic flexible cylinder having a high-tack surface and may be fitted at the ends thereof with suitable mounting apparatus such as retaining cups, stub shafts, or other known means for rotatably coupling a roller to a frame.  
           [0008]    In operation for cleaning, either the frame is advanced towards the surface to be cleaned or the surface is advanced towards the frame, such that the roller is fully engaged with the surface, preferably across the entire length of the roller. The surface then may be rollably moved past the roller when stationary, or the surface may remain stationary and the frame may be moved to translate the roller rollably over the stationary surface, the roller surface conforming to non-planarities in the substrate surface.  
           [0009]    A flexible contact cleaning roller in accordance with the invention may be readily incorporated into cleaning apparatus and uses already well known in the art, for example, multiple-roller arrangements having pivoting or turreted frames; stationary or roller-oscillating systems; secondary cleaning rollers for cleaning particles from the flexible cleaning roller; and other forms of flexible roller cleaning stations. Such a roller is suitable for cleaning both planar and non-planar surfaces. 
       
    
    
       [0010]    The foregoing and other objects, features, and advantages of the invention, as well as presently preferred embodiments thereof, will become more apparent from a reading of the following description in connection with the accompanying drawings in which:  
         [0011]    [0011]FIG. 1 is an elevational cross-sectional view of a first embodiment of a flexible contact cleaning roller in accordance with the invention;  
         [0012]    [0012]FIG. 2 is an elevational cross-sectional view of a second embodiment, showing a monolithic roller element supported for rotatable mounting by a cup-shaped receiver;  
         [0013]    [0013]FIG. 3 is an elevational cross-sectional view of a third embodiment, showing a monolithic roller element having a cast or inserted stub shaft for rotatable mounting;  
         [0014]    [0014]FIG. 4 is a cross-sectional view of a flexible roller in accordance with the invention supported by a frame and flexed into full contact with a curved substrate surface to be cleaned; and  
         [0015]    [0015]FIG. 5 is a cross-sectional view of a roller in accordance with the invention, showing the roller being urged by a backing roller or other urging means into rolling contact with a undulatingly non-planar substrate surface. 
     
    
       [0016]    Referring to FIG. 1, a first embodiment  10  of a flexible contact cleaning roller in accordance with the invention includes an inner element  12 , which may be an axially-flexible through-shaft, core, or mandrel  14  as shown, having protruding ends  16  for mounting roller  10  rotatably in a supporting and positioning frame  32  such as is shown in FIG. 4. Shaft  14  has an axis of rotation  15  and may be formed of any convenient material capable of axial flexibility and of being retained in rotatable fittings, such as bearings; for example, the shaft may be formed of polymers such as nylon and metals such as steel, aluminum, or other flexible alloys. Coaxially surrounding shaft  14  and supported by shaft  14  is a cylindrical outer element  18  having at least an outer surface  20  comprising a high-tack material, for example, polyurethane, silicone rubber, or adhesive tape, for conventional contact-roller cleaning of particles from a surface as is well-known in the art. Such cleaning means is well known and need not be elaborated here further. Outer element  18  may be cast onto inner element  12  or may be formed separately, with element  12  being inserted into element  18  in a subsequent step.  
         [0017]    Referring to FIGS. 2 and 3, second and third embodiments  10 ′, 10 ″ in accordance with the invention may be provided as a monolithic axially-flexible cylindrical roller element  18 ′ having no through-shaft inner element. Element  18 ′ may comprise material of high-tack throughout or may be formed of other flexible supportive material with only a high-tack surface layer  20 ′ disposed concentrically thereupon, as desired.  
         [0018]    Embodiment  10 ′ includes an adaptive holder  22  having a cup-shaped portion  24  for receiving and retaining an end of roller  18 ′ and a shaft portion  26  for rotatably mounting roller  18 ′ to a frame (not shown).  
         [0019]    Embodiment  10 ″ includes an adaptive stub shaft  28  disposed in an axial well  30  in roller element  18 ′, either by insert molding or by direct insertion of stub shaft  28  into a well  30  previously molded into element  18 ′, shaft  28  providing means for rotatably mounting roller  18 ′ to a frame (not shown).  
         [0020]    Referring to FIG. 4, a flexible contact cleaning roller, shown as  10  but equally capable of being  10 ′ or  10 ″, is rotatably retained at opposite ends in a frame  32 . Such rotatable retention may take any of various well-known forms as desired, including fixed bearings, pivotable bearings, spherically mounted bearings, bushings, journals, and the like, and need not be elaborated further here. A substrate  34  having a non-planar surface  36  requiring cleaning by high-tack surface  20  of roller  10  is disposed in relationship to frame  32  such that roller  10  is axially flexed into contact with surface  36  over the entire length thereof. Thus, in operation, when frame  32  and substrate  34  are translated relative to each other in a direction perpendicular to the page, inner element  14  and outer element  18  remain flexed and in contact with surface  36  while roller  10  rolls along surface  36 .  
         [0021]    Referring to FIG. 5, other types of non-planar surfaces may be cleaned by a flexible contact cleaning roller in accordance with the invention. Surface  36 ′ has a plurality of relative peaks  38 , 38 ′ and valleys  40 , 40 ′, 40 ″ not cleanable by prior art inflexible contact cleaning rollers. Roller  10  is disposed into relationship with substrate  34 ′ such that roller  10  makes continuous contact with surface  36 ′ from peak  38  through valley  40  and from peak  38 ′ through valley  40 ″. Further contact between peaks  38 , 38 ′ through valley  40 ′ may be provided by one or more narrow backing rollers, shown schematically as arrow  42 , disposed opposite to valley  40 ′ and urging roller  10  into contact therewith. Other such backing and urging means as may occur to one skilled in the art should be understood as being within the scope of the invention.  
         [0022]    From the foregoing description, it will be apparent that there has been provided an improved contact cleaning roller for cleaning planar and non-planar substrate surfaces, wherein an axially-flexible contact cleaning roller having a high-tack surface is capable of making cleaning contact with all portions of a non-planar substrate surface. Variations and modifications of the herein described flexible contact cleaning roller, in accordance with the invention, will undoubtedly suggest themselves to those skilled in this art. Accordingly, the foregoing description should be taken as illustrative and not in a limiting sense.