Abstract:
Disclosed are systems and methods for limiting movement of medium on an imaging apparatus comprising positioning the medium against an imaging surface, moving a moveable surface to sandwich the medium between the imaging surface and the moveable surface, and passing air through at least one opening disposed to reduce forces acting on the medium that are caused by air currents generated adjacent the imaging surface when the moveable surface is moved.

Description:
FIELD OF INVENTION  
         [0001]    The present invention generally relates to imaging of media, and more particularly to limiting media movement on an imaging apparatuses.  
         DESCRIPTION OF RELATED ART  
         [0002]    A basic format for different types of devices that capture images on a sheet of paper or other media include an imaging surface (referred to herein as a “platen”), e.g., a surface of a glass plate or a PLEXIGLAS® plate or a plate of other composition, adjacent which a medium, e.g., sheet of paper or other object, can be manually positioned for image processing. Such devices, which include copiers, scanners, facsimile machines, printers, and other document imaging apparatuses, often include a hinged lid or other movable surface adapted to come into contact with at least a portion of the medium placed adjacent the platen. The lid may be moved away from the platen (opened) to facilitate positioning media adjacent the platen, and the hinged lid also may be moved against media positioned adjacent the platen (closed) to maintain media in fixed positions during image scanning. However, when the lid or other movable surface is opened or closed adjacent an imaging surface resultant variations in ambient air pressure are brought about by the lid movement in the space adjacent the imaging surface. If a sheet of paper or other light-weight medium has been placed adjacent the platen, the induced ambient air pressure variations including partial vacuums that are caused by air pressure currents may result in the medium being moved from a desired position or even away from the platen.  
           [0003]    In the instance of moving a lid toward a previously-positioned medium, the produced variations in ambient air pressure may cause the medium to move so that resultant processed images are skewed or not centered at an operator-selected position. Because scanned images are now predominately digitized, software has been written to adjust scanned images for reproduction by rotation to correct for angular misalignments of media being scanned. Utilization of such software, however, increases cost and time for image processing and also system complexity.  
           [0004]    When an imaging apparatus lid is opened, a medium previously positioned adjacent the platen may be moved away from the platen by induced ambient air pressure variations that can include creation of a partial vacuum about the medium. If, as a result of the lid being opened, the medium is thereby caused to be moved away from the platen and adjacent the moving lid, the medium can be moved sufficiently far from the platen to have it fall off the imaging apparatus. Old or otherwise delicate documents, for example, can be damaged by so falling off an imaging apparatus.  
           [0005]    Clip type retainers have been attached to lid surfaces to preclude media from falling off imaging devices. An operator first would use the clip to attach a medium to be imaged to the lid. Then the operator would move the lid with the attached medium to be adjacent an imaging surface. When the lid with the attached medium is opened, the medium could be removed from the lid by releasing the clip from the medium. All of these operations, including being sure that the clipped medium is moved by the lid onto a correct position on an imaging surface, increase the time and effort required of an operator in scanning an image. Other unavoidable problems associated with using clips attached to imaging apparatuses—whether to lids or adjacent platens—are that clips, which must be flexed to attach or release media, will wear out and even break. Moreover, the use of such clips can obscure portions of the image to be processed.  
           [0006]    Lips or other protrusions on or adjacent imaging surfaces have been used to attempt to hold media in a desired position. However, such lips or protrusions typically do not restrict movement of a medium in all directions and, therefore, do not fully address the aforementioned media movement issues. Moreover, although often being somewhat effective in preventing a medium from falling off of an imaging surface, such lips or protrusions can result in damage to the media when forced against the surfaces of the lip or protrusion.  
           [0007]    A familiar technique operators have used so as to avoid having previously positioned media moved about or lifted away from imaging surfaces when lids are opened or closed is to reduce the speed at which lids are moved. Understandably, this approach increases the time required for scanning images, and usually, the media still shifts.  
         BRIEF SUMMARY OF THE INVENTION  
         [0008]    Embodiments provide a system for limiting medium movement on an imaging apparatus, the system comprising an imaging surface and a moveable surface disposed to be moved to sandwich the medium between the imaging surface and the moveable surface, and at least one air passage opening disposed to pass air through the moveable surface.  
           [0009]    Embodiments provide a system for limiting medium movement on an imaging apparatus, the system comprising an imaging surface, a moveable surface capable of being moved to sandwich the medium between the imaging surface and the moveable surface, and at least one air passage opening disposed adjacent the imaging surface to pass air away from the imaging surface when the moveable surface is moved.  
           [0010]    Embodiments provide a method for limiting movement of a medium on an imaging apparatus comprising positioning the medium against an imaging surface, moving a moveable surface to sandwich the medium between the imaging surface and the moveable surface, and passing air through at least one opening disposed to reduce forces acting on the medium that are caused by air currents generated adjacent the imaging surface when the moveable surface is moved. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    [0011]FIG. 1A is a perspective view of a prior art scanner with a lid partially closed;  
         [0012]    [0012]FIG. 1B is a perspective view of the prior art scanner of FIG. 1A with the lid fully open and off an imaging surface;  
         [0013]    [0013]FIG. 2 is a perspective view of an embodiment of a lid with pad and passages according to the present invention;  
         [0014]    [0014]FIG. 3 is a partial sectional view of a lid of one embodiment of the present invention showing passages with turns to attenuate light from passing through the lid;  
         [0015]    [0015]FIG. 4A is a perspective view of a scanner with a hinged lid having an arrangement of passages in accordance with an embodiment of the invention;  
         [0016]    [0016]FIG. 4B is a perspective view of a scanner with a hinged lid having an arrangement of passages in accordance with another embodiment of the invention;  
         [0017]    [0017]FIG. 5 is a perspective view of an embodiment of an imaging apparatus lid with a fabric covering having an open grid shown in phantom and openings through the fabric shown in a partial exploded view;  
         [0018]    [0018]FIG. 6 is a partial perspective view of an imaging apparatus lid with extending projections according to an embodiment of the invention; and  
         [0019]    [0019]FIG. 7 is a perspective view of a scanner with passages provided adjacent an imaging surface according to another embodiment of the invention. 
     
    
     DETAILED DESCRIPTION  
       [0020]    Referring to FIGS. 1A and 1B, an exemplary prior art scanner  101  is shown. The present invention is described here generally with reference to scanners that digitize scanned images from media such as documents, including sheets of paper, objects, etcetera. The present invention is not limited to use with scanners but instead is readily implementable with other image processing apparatuses without limitation, such as copiers, facsimile machines, printers, etc.  
         [0021]    Scanner  101 , as shown in FIG. 1A, includes hinged lid  102  in the process of being brought down onto platen  103  on which medium  104  to be scanned has been positioned. This movement of lid  102  produces movement of air away from platen  103  as is represented by arrows  105 . Such air movements  105  are forces that can cause movement or repositioning of medium  104  with respect to platen  103 , or even result in displacement of medium  104  off of platen  103 . In contrast, as shown in FIG. 1B, when lid  102  is being raised away from platen  103  movements of air back into spaces adjacent platen  103  are produced as shown by arrows  106 . Concomitant with air movements into spaces adjacent platen  103  that are produced by raising lid  102  is an initial reduced ambient air pressure, i.e., partial vacuum, adjacent lid  102  surface that was previously lowered onto platen  103 . Moving lid  102  induces forces, i.e., partial vacuums, that can move medium  104  adjacent platen  103  and/or lift medium  104  off of platen  103  and thereby temporarily “attach” medium  104  to lid  102 .  
         [0022]    Movements of medium  104  are caused by air movements  105  and  106  which are stochastic. Accordingly, an operator placing medium  104  on platen  103  can not predict the amount and directions of medium  104  movements that could be caused by moving lid  102 , or be informed as to how slowly lid  102  needs to be moved to prevent medium  104  from being moved by air movements  105  or  106 .  
         [0023]    The present invention overcomes these problems that can be caused by lowering and raising lid  102  with respect to a medium  104  positioned on platen  103 .  
         [0024]    [0024]FIG. 2 illustrates a perspective view of lid  201  incorporating one embodiment of the present invention. Specifically, lid  201  includes openings  202  to permit air that otherwise would be compressed by movement of lid  201  to pass through lid  201  and to thereby substantially not be displaced by lid  201  movements. Conversely, openings  202  in providing for passage of air through lid  201  also mitigate ambient air pressures from being reduced by movements of lid  201 .  
         [0025]    As shown in FIG. 2, lid  201  includes pad  203 , which when lid  201  is brought toward platen  103  provides a cushion to rest against medium  104  that is positioned adjacent platen  103 . Pad  203  of embodiments of the invention may comprise a resilient or compressible material, such as may be formed from a foamed material. Openings  202  for the embodiment shown in FIG. 2 are preferably continuous through both pad  203  and lid  201  to enable air to move through lid  201  and thereby minimize air pressure fluctuations induced by motion of lid  201 .  
         [0026]    Referring to FIG. 3, openings  202  in lid  201  are shown to incorporate turns and to be continuous. The continuity of openings  202  provides for air to move through lid  201 . By incorporating turns, or other adaptations, such as baffles, in openings  202  the transmission of light through openings  202  and onto platen  103  is attenuated. This attenuation of light transmission promotes provision of platen  103  with an uniform background environment for effective imaging.  
         [0027]    Referring to FIG. 4A, scanner  101  can include hinge  401  for attachment of lid  201 . As such, hinge  401  establishes axis A-A about which lid  201  can be rotated toward and away from platen  103 . It will be appreciated that rotational movement of lid  201  toward and away from platen  103  results in less air being moved by lid  201  as the distance along lid  201  away from axis A-A decreases, whereas an increased volume of air is encountered and can be moved by lid  201  as the distance along lid  201  away from axis A-A increases. To address this situation one embodiment of the present invention includes increased numbers of or sizes for openings  202 , or both, as distances along lid  201  away from axis A-A increase. Such increase(s) for openings  202  (as shown in FIG. 4B) provide for channeling more air through lid  201  as distances along lid  201  away from axis A-A increase.  
         [0028]    Referring to FIG. 5, where another embodiment for the present invention is shown, large volume open grid patterns  501  are provided through lid  502 . For this embodiment, openings in lid  502  are provided by a combination of open grid patterns  501  and openings  503  in fabric  504  covering open grid patterns  501 . Openings  503  in fabric  504  can be holes through fabric  504 , or can be provided by spacings between threads woven to form fabric  504 , or can be provided by both holes and spacings between woven threads.  
         [0029]    Referring to FIG. 6, an embodiment for the present invention is shown having projections  601  extending from lid  602 . When lid  602  with projections  601  is lowered onto platen  103 , air passes between projections  601 . Medium  104  is pressed by projections  601  against platen  103  as lid  602  is closed with respect to platen  103 . Alternatively, when lid  602  is moved away from platen  103 , air again is passed between projections  601  to attenuate air pressure variations about medium  104 . A combination of both projections  601  and openings  202  through lid  602  can be used to attenuate air pressure variations.  
         [0030]    Referring to FIG. 7, another embodiment for the present invention provides openings  701  in housing  705  adjacent platen  103 . Here openings  701  incorporate turns so air currents produced by lid  102  movements are passed from adjacent platen  103  to distanced side openings  702  on scanner  703 . For instance closing lid  102  toward medium  104  positioned against platen  103  results in air being passed through openings  701  and  702  as shown by air movements  706 . Openings  202 , as shown in FIGS. 2, 4A,  4 B and  6 , including openings  501  and  503 , as shown in FIG. 5, and also projections  601 , as shown in FIG. 6, can be combined separately or in combinations with openings  701  of this embodiment.