Abstract:
A new media path includes a flexible member that cooperates with a control point for smooth transitions of media sheets along the path. The media path includes an elongated member having a first end and a second end, the elongated member having a longitudinal axis and a cross-member axis perpendicular to the longitudinal axis, the elongated member having a first surface that is non-linear in at least one of the longitudinal and cross-member axes, and a bevel on a second surface of the elongated member, the bevel being proximate to the first end of the elongated member at a predetermined distance from the first end.

Description:
TECHNICAL FIELD 
       [0001]    The apparatus described below relates to guides that direct media sheets through a media path in a printer, and more particularly to guides that allow printer components and subassemblies to rotate and bidirectionally translate the media sheet without jamming the corners or edges of the media sheet against the guides. 
       BACKGROUND 
       [0002]    In a typical printer, media trays store media sheets within the printer. During the printing cycle, a media transport system retrieves media sheets from a tray, routes the media through the printer to receive an image, and then ejects the media into an output tray for collection by a user. In some printers, separate media handling components or printer subassemblies perform the functions described above. For example, the printer could include a subassembly that retrieves a single media sheet from a stack of media and then transfers the sheet to another subassembly that conveys the sheet to a print head or image drum where the media sheet receives an image. In order to deliver an acceptable product to the user, each subassembly should transfer media sheets to the next subassembly without jamming or damaging the sheet. 
         [0003]    Manufacturers refer to the junction between two printer subassemblies as a media path transition. Media path transitions include guides or baffles that position the media sheet for proper reception by the next subassembly. Typically, the guides include a surface that transfers the media sheet without jamming the edges or bending the corners. The characteristics of the guide depend on the functionality of the printer component or subassembly upon which the guide operates. For example, some subassemblies transport media in two directions, while other subassemblies rotate the media sheet. Still other subassemblies include access doors that open to allow a user to inspect the condition of the media path. Therefore, different subassemblies require different types of guides to direct media across the media path transition. 
         [0004]    When guiding media subject to bidirectional movement, manufacturers commonly utilize wide baffle openings or “funnels,” preceded by a control point. Each funnel includes two opposing surfaces that form a gradually constricting media path, thereby directing the media sheet into the control point. The control point includes an idler and drive roller pair. The idler roller rests upon the drive roller to form a nip. As the funnel directs media into the nip, the roller pair accurately directs the media sheet across the media path transition to the next printer component or subassembly. For an even greater level of accuracy, the receiving subassembly may include a second roller pair preceded by a second funnel to accept the media sheet. Wide baffle openings and control points effectively direct bidirectional media between printer subassemblies; however, printers commonly use other types of guides as well. 
         [0005]    Another type of guide utilizes interdigitated or interlaced “fingers” to transition the media between printer subassemblies. In a typical arrangement, the output of a subassembly includes a first member that spans the width of the media path. The member includes a plurality of fingers or curved protrusions that extend away from the media path. Adjacent fingers of the first member are separated by a distance that enables the fingers on a second member to be received between the adjacent fingers of the first member. Similarly, the fingers of the first member fill spaces between adjacent fingers in the second member. Thus, the interdigitated fingers form a continuous and overlapping surface, for directing media sheets along a path. Generally, such interdigitated finger media guides work well; however, some types of interdigitated finger arrangements may present structure to rotating media that may catch corners or edges of certain types of media. 
       SUMMARY 
       [0006]    A new media path includes a flexible member that cooperates with a control point for smooth transitions of media sheets along the path. The media path includes an elongated member having a first end and a second end, the elongated member having a longitudinal axis and a cross-member axis perpendicular to the longitudinal axis, the elongated member having a first surface that is non-linear in at least one of the longitudinal and cross-member axes, and a bevel on a second surface of the elongated member, the bevel being proximate to the first end of the elongated member at a predetermined distance from the first end. 
         [0007]    The media path may be incorporated in a printer. The printer includes a drive roller coupled to an actuator, an idler roller that contacts the drive roller to form a nip that transfers a media sheet through the nip to a media transport apparatus having an elongated member and a pivot member, the pivot member being configured to move between a first position and a second position, and the elongated member having a first end and a second end, a longitudinal axis extending between the first end and the second end, a cross-member axis perpendicular to the longitudinal axis, a first surface that is non-linear in at least one of the longitudinal and cross-member axes, and a bevel on a second surface of the elongated member, the bevel being proximate to the first end of the elongated member at a predetermined distance from the first end to enable the first end of the elongated member to abut a media transport platform in response the pivot member being in the second position. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    Features for transitioning media sheets between printer subassemblies are discussed with reference to the drawings. 
           [0009]      FIG. 1A  is a side view of a media transport path with an interface that facilitates movement of media between subassemblies in one direction. 
           [0010]      FIG. 1B  is a side view of the interface of  FIG. 1A  shown facilitating movement of media between subassemblies in a direction opposite to that shown in  FIG. 1A . 
           [0011]      FIG. 2  depicts a side view of a media transport apparatus having an elongated member formed of a flexible material and a pivotable media path access door. 
           [0012]      FIG. 3  depicts a side view of a media transport apparatus having an elongated member with a pivot point and a biasing member to bias the first end of the elongated member away from the media path. 
           [0013]      FIG. 4  depicts a perspective view of the media transport apparatus having a biasing member that includes a set of springs positioned along the second surface of the member. 
           [0014]      FIG. 5  depicts a perspective view of the fingers having sloped side surfaces and being interdigitated with a coordinating set of fingers. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    The word “printer” as used herein encompasses any apparatus, such as a digital copier, bookmaking machine, facsimile machine, multi-function machine, etc. which performs a print outputting function for any purpose.  FIG. 1A  depicts a portion of a media transport system at an interface  10  between printer subassemblies. The interface  10  enables media  14  to transition between printer subassemblies with reduced risk of travel interference. The interface  10  includes a guide platform  18 , and a moving member  20 . The moving member  20  may either translate or pivot with respect to guide platform  18  to extend the media path provided by platform  18 . The bevel  24  on the platform  18  matches the bevel on the member  20 . This complementary fit reduces the profile of edges, which may be present at the interface  10 . 
         [0016]    Media may move either from right to left or left to right. In the left to right direction, the leading edge of the media  14  drops from the platform  18  to the member  20  without engaging the interface  10  as the interface is positioned at a predetermined distance from the termination  28  of the platform  18 . The predetermined distance is selected with reference to a curl distance. Curl distance refers to media sheets becoming curled due to the shape of some article in a printer media path. For example, curl distance may refer to the distance between the exit side of a roller pair nip and the exhibition of curl in a leading edge of the media sheet exiting the nip. A heavily curled media sheet exhibits a short curl distance, while a flat media sheet exhibits a long curl distance. In order to provide a continuous media path, the bevel of member  20  abuts platform  18  at a distance from termination  28  before media traveling left to right exhibits a curl likely to engage the interface  10 . Similarly, the leading edge of media moving from right to left may strike the platform  18  below the termination  28 , but the slope of the platform at interface  10  urges the media upwards onto the platform  18 . The bevel in the member  20  enables the interface  10  to be restored even though the member is pivoted or translated with respect to platform  18 . In a like manner, an interface  10  may be implemented at the upper surface of a media path to enable upwardly curling media to pass through subassembly interfaces without engaging movable surfaces. 
         [0017]    Incorporation of the interface  10  in a media path within a printer is shown in  FIG. 2 . The elongated member  114  includes three sections; namely, a guide arm  138 , a media guide  142 , and a “finger” interface  146 . Each section of the elongated member may be integrated in a single structure, or each section may also be a distinct element with the elements coupled to one another. The media guide  142  may be formed of a rigid material, such as plastic. The lower surface  154  of the media guide  142  forms a gap with the media path base  134 . Media travels smoothly between the lower surface  154  and the path base  134 , because the lower surface  154  does not include features that present a significant risk of catching the edges of a media sheet. The upper surface  150  of the media guide  142  includes structure for attaching the upper surface  150  to the printer frame  118 . In the embodiment illustrated in  FIG. 2 , the media guide  142  includes attachment points  158  that extend through openings in the printer frame  118 . 
         [0018]    The guide arm  138  is biased against pivot member  122 , referred to herein as a media access door  122 . The access door  122  includes an idler roller  126  and an inner surface  166 . When the access door  122  is opened the media path is exposed. When the access door  122  is closed, the idler roller  126  contacts the drive roller  130  to form a nip between the rollers  126  and  130 . Also, when the access door  122  is closed, the guide arm  38  contacts the inner surface  166  of the access door  122  to provide a continuous surface upon which the roller pair  126  and  130  can transfer a media sheet without damaging the media sheet. In particular, the tip, or first end, of the guide arm  38  contacts the inner surface  166  at a distance less than a curl distance from media exiting the nip, as explained above. 
         [0019]    In one embodiment, the guide arm  138  includes a protrusion  170  that contacts the inner surface  166  of the media access door  122 , as illustrated in  FIGS. 2 and 3 . The protrusion  170  is made of a durable material that resists wear, but has a low coefficient of friction so that the protrusion  170  slides easily along the inner surface  166  of the access door  122 . The protrusion  170  is connected to the surface of the guide arm  138  proximate the inner surface  166  of the media access door  122 . In one embodiment, the protrusion  170  is a plurality of separated raised segments that collectively span the width of the guide arm  138 . In another embodiment, the protrusion  170  is a single unit that spans the width of the guide arm  138 . 
         [0020]    The protrusion  170  protects the tip of the guide arm  138  from becoming worn or damaged as the outboard end of arm  138  repeatedly contacts the inner surface  166  of the media access door  122 . To illustrate, as the door  122  nears the closed position, the protrusion  170  contacts the inner surface  166 . The thickness of the protrusion  170  prevents the tip of the guide arm  138  from contacting the inner surface  166 . As the door  122  is further closed, the pressure from the inner surface  166  upon the protrusion  170  causes the guide arm  138  to bend. The resistance offered by the guide arm  138  maintains the position of the protrusion  170  against the inner surface  166 . Furthermore, as a user closes the door  122 , the inner surface  66  acts on the protrusion  170  to position the tip of the guide arm  138  at a distance from the roller pair  126  and  130  less than the curl distance. The length of the guide arm  138  orients the tip of the guide arm  138  at a distance less than the curl distance from the roller pair  126  and  130  even if the access door  122  does not return exactly to the same place each time the door  122  is closed. Thus, the guide arm  138  is able to form a smooth transition surface between the media guide  142  and an access door  122  even though the access door  122  fails to close to the same position always. 
         [0021]    To bias the tip of the guide arm  138  against the inner surface  166 , the guide arm  138  may exhibit a curved and flexible profile, as illustrated in  FIG. 2 . In such an embodiment, when the access door  122  remains in an open position the guide arm  38  exhibits a curvature away from the path base  134 . As the door  122  is closed, the protrusion  170  makes contact with the inner surface  166  before the door  122  reaches the fully closed position. As the door  122  is further closed, the inner surface  166  urges the protrusion  170  and arm  138  toward the roller pair  126  and  130  to flatten or bend the guide arm  138 . 
         [0022]    In another embodiment, as illustrated in  FIG. 3 , the guide arm  138  and the media guide  142  are structural elements that are distinct from the finger interface  146 . In such an embodiment, the guide arm  138  and the media guide  142  include a pivot point  174  and an attachment point  158 . The guide arm  138  maintains a curvature away from the path base  134 ; however, in this embodiment the guide arm  138  also includes a biasing member  182 . The biasing member  182  is coupled between the frame  118  and the arm  138  to urge the guide arm  138  away from the path base  134  when the access door  122  is in the open position. When a user closes the access door  122 , the inner surface  166  contacts protrusion  170  before the door  122  becomes fully closed. When force exerted by the user exceeds the resistive force exerted by the biasing member  182 , the force from the user against the inner surface  166  causes the guide member  138  to pivot about the pivot point  174  toward the path base  134 . The resistive force from the biasing member  182  keeps the protrusion  170  firmly pressed against the inner surface  166  as the user completely closes the door  122 . 
         [0023]    The biasing member  182 , as illustrated in  FIG. 3 , cooperates with the attachment point  158 . The biasing member  182  can be any suitable device that biases the guide arm  138  away from the path base  134 , such as a spring or an elastomeric member. In one embodiment, the biasing member  182  connects the attachment point  158  to the printer frame  118 . As illustrated in  FIG. 4 , the guide arm  138  may contain a series of attachment points  158  that span the width of the guide arm  138 . In such an embodiment, the attachment points  158  include posts  186  that extend through openings in the printer frame  1   18 . The biasing member  182  is a spring that surrounds the post  186 . The bottom of the spring is connected to the base of the attachment point  158  and the top is connected to a cap  190  upon the top of the post  186 . When the access door  122  is opened, the spring contracts and pivots the guide arm  138  away from the path base  134 . Of course, many other embodiments are possible that bias the guide arm  38  away from the path base  134 . 
         [0024]    At the other end of the media elongated member  114  is the finger interface  146 . As illustrated in  FIG. 4 , the finger interface  146  contains a plurality of fingers  194  or lobes that interdigitate or interlace with a corresponding set of fingers  198  on the next printer subassembly. The finger interface  146  may be separable or integral with the media guide  142  and guide arm  138 . When the finger interface  146  is a distinct element, posts  186  connect the finger interface  46  to the media guide  142  and/or printer frame  1   18 . The finger interface  146  is made of a rigid material, usually plastic; however, any rigid material having a substantially smooth surface may be utilized. As explained below, the fingers  194  form a smooth transition between the media transport system  110  and the next printer subassembly. 
         [0025]    As illustrated in  FIG. 2 , the lower surface of the fingers  194  is sloped away from the path base  134 . The degree or curvature of the slope depends on the particular embodiment, but in most embodiments the slope should permit the lowest portion of each fingertip  202  to reside above the plane formed by the bottom surface of the fingers  198  on the next printer subassembly, as illustrated in  FIGS. 2 and 3 . When the fingertips  202  are above the aforementioned plane, the interdigitated fingers form a continuous surface. 
         [0026]    To provide a surface even less likely to cause the edges of the media sheet to become jammed, the sides of the fingers  194  may also include a slope, as illustrated in  FIG. 5 . Similarly, the fingers  194  may include a partially rounded cross section. In both embodiments, the sides of the fingers  194  do not include sharp corners that present a significant risk of catching the edges of the media sheets, should the next printer subassembly rotate the media sheet. Of course, the side surfaces of the fingers  194  also permit media sheets to travel under the interdigitated fingers  194  and  198  in either the forward or reverse directions. 
         [0027]    In operation, a media sheet enters the nip formed by the roller pair  126  and  130 . The biasing member  182  or the flexible nature of the guide arm  138  positions the leading edge of the guide arm  138  less than the curl distance away from the roller pair  126  and  130 . As a result, the roller pair  126  and  130  transports the media sheet toward or away from the media transport system  110  or even rotates the media sheet, because the guide arm  138  presents a smooth and continuous surface to the edges of the media sheet. Next, the roller pair  126  and  130  transports the leading edge of the media sheet in the gap formed by the media guide  142  and the media path base  134 . Finally, the roller pair  126  and  130  transports the leading edge of the media sheet smoothly under the fingers  194  of the finger interface  146  and into the region of the next printer subassembly. The sloped or rounded side surfaces of the interdigitated fingers  194  and  198  permit the next printer subassembly to transport the media sheet forward or backward, and also rotate the media sheet, because the fingers  194  present guiding structure with relatively little, if any, structure that can catch the edges of the media sheet. 
         [0028]    In response to users opening the access door  122  to inspect the condition of the media path or to clear a paper jam, the protrusion  170  interacts with the access door  122  to position the outboard end of the arm  138  so that the risk of media catching an edge is substantially reduced. The interaction of the inner surface  166  and the protrusion  170  effectively reduces the risk of media catching an edge, even though the access door  122  does not return to the same position each time it is closed. Also, the finger interface  146  allows a user to remove and install the media transport system  110  and the next printer subassembly easily, without requiring a tedious alignment of the structure forming the media path. Instead, a smooth media transition surface is provided by simply interdigitating the fingers  194  on the media transport system  110  with the fingers  198  on the next printer subassembly. Finally, even though the media transport system  110  has been illustrated in a horizontal configuration, the system  110  works equally well in other orientations. 
         [0029]    It will be appreciated that variations of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.