Abstract:
The invention is directed to a media tray for an imaging apparatus for receiving a sheet of media. The media tray includes a base having a first side region and a second side region, a first sheet support member, a second sheet support member, a first mechanism, a second mechanism, and a force applying mechanism. The first and second mechanisms pivotally couple the first and second sheet support members to the side regions of the base, respectively. The force applying mechanism applies a force on the first and second sheet support members such that each of the first and second sheet support members diverge upwardly and outwardly from the base. The force applying mechanism includes a first cam member or first spring mechanism positioned between the first sheet support member and the base and a second cam member or second spring mechanism positioned between the second sheet support member and the base.

Description:
TECHNICAL FIELD OF INVENTION 
     The present invention relates to a media exit or output tray for an imaging apparatus, and more particularly, to a retractable media exit or output tray for an ink jet printer. 
     BACKGROUND OF THE INVENTION 
     Most ink jet printers include some method of providing for a tray or bin to hold media once the media exits the printer. Early trays consisted of a flat tray that held the media in a flat fashion. The printing speed of early printers was slow enough so as to allow for the ink on a printed sheet of media to dry before the next sheet of media was positioned on top of the previous sheet. 
     As printing speeds increased, the ink on a printed sheet of media was unable to dry before the next sheet of media was positioned on top of the previous sheet. Hence, the ink would often smudge due to the contact with the next sheet of media. Some attempts have been made to address this problem by adjusting the drying properties of the ink. Other attempts have focused on methods of processing the media. For example, several printers have elaborate devices that tilt and kick the media onto staging platforms that are later actuated to allow the media to drop onto the surface of the tray. Other attempts have been directed to mechanisms which actively or passively hold the media such that the media&#39;s transverse cross section is concave. 
     Although the aforementioned attempts have addressed ink smudging problems with various degrees of success, they typically require complex, non-compact mechanisms or special media. Furthermore, the complexity of the mechanisms lend themselves to a higher probability of breakdown and higher costs. Also, the size of the mechanisms consume valuable desk space and are cumbersome to use. Thus, a need exists for a media exit tray with a simple design that addresses the ink drying problem, and is retractable within the printer to reduce the space required for the printer. 
     SUMMARY OF THE INVENTION 
     The invention is directed to a media tray for an imaging apparatus for receiving a sheet of media. The media tray includes a base having a first side region and a second side region, a first sheet support member, a second sheet support member, a first mechanism, a second mechanism, and a force applying mechanism. The first and second mechanisms pivotally couple the first and second sheet support members to the side regions of the base, respectively. The force applying mechanism applies a force on the first and second sheet support members such that each of the first and second sheet support members diverge upwardly and outwardly from the base. The force applying mechanism can be either a cam or spring mechanism. 
     In one preferred embodiment, a media tray for receiving a sheet of media transported thereto from an imaging apparatus includes a base and a media support assembly. The media support assembly is moveably coupled to the base and includes at least one cam member that engages an inclined region of the base. The at least one cam member forces an outer portion of said media support assembly to move upwardly relative to the base when the media support assembly is moved in a first direction relative to the base. The base is slideably coupled to the imaging apparatus. 
     The media support assembly includes a base extension having a first side region and a second side region positioned above the base. The base extension is slideably coupled to the base. The media support assembly also includes a first and second sheet support member, each of which is pivotally coupled to the first and second side regions of the base extension, respectively. Each of the first and second sheet support members includes a downwardly extending cam member having a cam surface for engaging the inclined region of the base. As the base extension is slid outward from the base, the first and second cam surfaces engage the inclined region of the base to force each of the first and second sheet support members to pivot upward and away from the base. 
     Other features and advantages of the invention may be determined from the drawings and the detailed description of the invention that follows. Corresponding reference characters indicate corresponding elements throughout the several figures. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 is a perspective view of an ink jet printer incorporating a retractable exit tray of the present invention shown in the retracted position; 
     FIG. 2 is a perspective view of the ink jet printer of FIG. 1 with the exit tray shown in the extended position; 
     FIG. 3 is a perspective view of the ink jet printer of FIGS. 1 and 2 with the exit tray shown in the extended position and the bottom printer frame detached from the printer housing; 
     FIG. 4 is a perspective, top view of a base portion of the cam embodiment of the exit tray; 
     FIG. 5 is a perspective, top view of a base extension portion of the cam embodiment of the exit tray; 
     FIG. 6 is a perspective, bottom view of a wing portion of the cam embodiment of the exit tray; 
     FIG. 7 is a perspective, bottom view of a wing portion of the spring embodiment of the exit tray; 
     FIG. 8 is a diagrammatic side view of an ink jet printer showing a sheet of media being fed through a printing zone and onto the cam embodiment of the exit tray; 
     FIG. 9 is a diagrammatic side view of an ink jet printer showing a sheet of media being fed through a printing zone and onto the spring embodiment of the exit tray; and 
     FIG. 10 is a front elevation view of the exit tray of the invention during a normal print operation. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIGS. 1-3 show an ink jet printer  100  incorporating an exit tray  102  of the present invention. Printer  100  further includes a housing  104  and a bottom frame member  106 . As shown in FIG. 1, exit tray  102  is positioned in a retracted position when the printer  100  is not in use. As shown in FIG. 2, exit tray  102  is positioned in an extended position to receive print media, such as one or more sheets of paper, during a printing operation. FIG. 3 shows printer  100  of FIGS. 1 and 2 with bottom frame member  106  detached from housing  104  and exit tray  102  in the extended position. 
     Exit tray  102  includes a base  108 , a base extension  110 , a first sheet support member  112 , and a second sheet support member  114 . With reference to FIGS. 1-11, the structure and function of exit tray  102  will be discussed in greater detail. 
     Referring now to FIG. 3, base  108  is slideably coupled to bottom frame member  106 . Bottom frame member  106  includes two L-shaped guides  146 ,  148  which slideably engage two corresponding base L-shaped guides (not shown) of base  108  to form a translational joint. Frame guides  146 ,  148  extend from an upward-facing frame surface  150  and are located in a central, recessed portion  144  of bottom frame member  106 . Base  108  slides in a generally horizontal plane relative to bottom frame member  106 . Base  108  is slid into frame recessed portion  144  when exit tray  102  is in the retracted position and is extended from frame recessed portion  144  when exit tray  102  is in the extended position. Alternative methods could be used to couple base  108  to bottom frame member  106 , such as for example, a roller-track assembly, so long as the coupling means allows base  108  to move along a linear axis in a plane generally parallel to the plane of bottom frame member  106 . 
     As shown in FIG. 4, base  108  further includes two L-shaped guide channels  156 ,  158  which slideably receive corresponding L-shaped guides  160 ,  162  of base extension  110  (see FIG.  5 ). Base guide channels  156 ,  158  are located within a transversely centered base recess portion  152  generally below an upper surface  154  of base  108 . Base extension  110  is disposed generally within base recess  152  when exit tray  102  is in the retracted position and is extended outwardly from base recess  152  when exit tray  102  is in the extended position. Alternative methods could be used to couple base extension  110  to base  108 , such as for example, a roller-track assembly, so long as the coupling means allows base extension  110  to move along a linear axis in a plane substantially parallel to the plane of base  108 . 
     Base  108  further includes in base recess portion  152  two detent members  164 ,  166  to impede the initial extension of base extension  110  relative to base  108 . Detent members  164 ,  166  engage two detent grooves  168 ,  170  in extension guide channels  160 ,  162 . Detent members  164 ,  166  are shown as flexible cantilever arms which snap into detent grooves  168 ,  170  when base extension  110  is disposed within base recess portion  152 . Alternative structure could be employed to impede the initial movement of base extension  110  relative to base  108 , such as for example, a raised bump portion on base extension  110  which engages a recessed divot portion on base  108 . 
     As shown in FIG. 5, base extension  110  further includes a first pair of slotted apertures  186 , a second pair of slotted apertures  188 , a third pair of slotted apertures  190  and a fourth pair of slotted apertures  192 . The slotted aperture pairs are used to pivotally couple first sheet support member  112  and second sheet support member  114  to base extension  110 . 
     Referring to FIG. 6, first sheet support member  112  includes two clip pairs  198 ,  200  extending from a surface  202  in a region near a proximal end  210 . Clips  198 ,  200  engage the two clip receiving aperture pairs  186 ,  188  formed in extension surface  180  of base extension  110  to form a rotational joint. Clip  198  includes a left and a right, partially cylindrical members  199 ,  201  whose cylindrical axes are aligned to each other. Clip  200  includes a left and a right, partially cylindrical members  203 ,  205  whose cylindrical axes are aligned to each other. The aligned cylindrical axes of clips  198 ,  200  define a pivot axis (P 1 ) of first sheet support member  112 . Alternative methods could be adopted to pivotally couple first sheet support member  112  to base extension  110 , such as for example, a standard hinge. 
     Second sheet support member  114  has two clips (not shown) which engage the two clip receiving aperture pairs  190 ,  192  formed in extension surface  180  of base extension  110 . The structure and function of the clips of second sheet support member  114  are identical to clips  198 ,  200  of first sheet support member  112 . It should be noted that second sheet support member  114  is generally a mirror image of first sheet support member  112 . Therefore, all structure and function disclosed herein for first sheet support member  112  should be understood to be applicable to the structure and function of second sheet support member  114 , unless otherwise stated. 
     When exit tray  102  is in the retracted position (see FIG.  1 ), the upper surface  230  of first sheet support member  112 , the upper surface  232  of second sheet support member  114  and the upper surface  184  of a raised, central portion  182  of base extension  110  are generally co-planer. When exit tray  102  is in the extended position (see FIG.  2 ), a distal end  208  of first sheet support member  112  and a distal end  212  of second sheet support member  114  are raised upward relative to extension surface  184  and the proximal ends  210 ,  214  of first and second sheet support members  112 ,  114 , respectively. The proximal ends  210 ,  214  of sheet support members  112 ,  114  are pivotally coupled to base extension  110  as described above and remain adjacent to base extension  110 . 
     Referring to FIG. 6, in one embodiment of the present invention, (also referred to as the cam embodiment), the upward movement of distal ends  208 ,  212  of sheet support members  112 ,  114  is caused because first sheet support member  112  and second sheet support member  114  each further include a downwardly extending cam member  204  which engages upper surface  154  of base  108 . Cam member  204  includes a cam surface  206 . When exit tray  102  is in the retracted position, cam members  204  of sheet support members  112 , 114  are each disposed within a cam recess  172 ,  174 , respectively, located in base  108  (see FIG.  4 ). Each cam recess  172 ,  174  has a tapered surface  176 ,  178 , respectively, which extends downwardly from base upper surface  154 . When exit tray  102  is in the extended position, cam members  204  of first and second sheet support members  112 ,  114  are disposed forward of cam recesses  172 ,  174  and cam member surfaces  206  rest upon base upper surface  154 . 
     Referring to FIG. 7, in another embodiment of the present invention (also referred to as the spring embodiment), cams  204  are replaced by downwardly extending leaf springs  226 . Accordingly, the upward movement of distal ends  208 ,  212  of first sheet support member  112  and second sheet support member  114  results from an upward force generated by leaf springs  226 . When exit tray  102  is in the retracted position, leaf springs  226  are compressed generally against sheet support members  112 ,  114  and against base upper surface  154 . Since leaf springs  226  flex, base cam recesses  172 ,  174  are not required in base  108 . In the retracted position, a downwardly facing surface  228  of frame member  106  applies a downward force on the upper surfaces  230 ,  232  of first and second sheet support members  112 ,  114 . When exit tray  102  is in the extended position, first and second sheet support members  112 ,  114  are forward of frame surface  228  and the compression of leaf springs  226  is relieved to thereby lift distal ends  208 ,  212  of sheet support members  112 ,  114 . 
     The interaction between the various components in the embodiments of exit tray  102  will now be explained through a discussion of: (a) the relationship between the components in the retracted position, (b) as the components are moved from the retracted position to the extended position, (c) components in the extended position, and (d) as the components are moved from the extended position to the retracted position. 
     When the cam embodiment of the present invention is in the retracted position (see FIG.  1 ); base  108 , base extension  110 , first sheet support member  112  and second sheet support member  114  are generally within the recessed portion  144  of bottom frame member  106  (see FIG.  3 ). Base extension  110 , first sheet support member  112  and second sheet support member  114  are generally co-planar relative to each other and disposed generally above base  108  such that base extension detent grooves  168 ,  170  (see FIG. 5) engage base detent members  164 ,  166  (see FIG.  4 ), and such that cam members  204  are within base cam recesses  172 , 174 . 
     The cam embodiment of exit tray  102  is moved from the retracted position (see FIG. 1) to the extended position (see FIG. 2) by the application of an outward force by a user on a grip surface  196  of a grip portion  194  of base extension  110 . Initially base  108 , base extension  110 , sheet support members  112 , 114  all move outward together. This is because detent members  164 ,  166  (see FIG. 4) have a larger force threshold than the translational joint between base  108  and bottom frame  106 . Once base  108  is fully extended, the force threshold of detent members  164 ,  166  is overcome and base extension  110  slides relatively outward or forward from base  108 . As base extension  110  slides outward relative to base  108 , cam surface  206  (see FIG. 6) of first sheet support member  112  travels up base cam surface  176  (see FIG. 2) thereby forcing first sheet support member  112  to rotate at clips  198 ,  200  such that distal end  208  of right sheet support member  112  is raised relative to proximal end  210 . The distal end  212  of the second sheet support member  114  is raised relative to proximal end  214  by identical means. 
     Once the cam embodiment of exit tray  102  is in the extended position (see FIG.  2 ), cams  204  are forward of base cam recesses  172 ,  174  and each cam surface  206  of cams  204  of sheet support members  112 ,  114  rests on base upper surface  154 . Base  108  may be held in the extended position, for example, by positioning detent members on bottom frame member  106  to engage base  108 . 
     The cam embodiment of exit tray  102  is moved from the extended position to the retracted position by the application of an inward force by the user on grip  194  to force base extension  110 , first sheet support member  112  and second sheet support member  114  to slide inward relative to base  108 . As the sheet support members  112 ,  114  slide inward, cam surfaces  206  of cams  204  slide back down tapered surfaces  176 ,  178  and into base cam recesses  172 ,  174  (see FIG.  2 ). As cam surfaces  206  slide down tapered surfaces  176 , 178 , distal ends  208 ,  212  of sheet support members  112 ,  114  rotate downward until they are generally co-planar with base extension  110 . Once base extension  110  detent grooves  168 ,  170  (see FIG. 5) engage base detent members  164 ,  166  (FIG.  4 ), base extension  110  is fully retracted and first and second sheet support members  112 ,  114  are generally co-planar with base extension  110 . Base  108  then slides into the bottom frame recess portion  144  of bottom frame member  106 , and below downward-facing surface  228  of housing  104 . 
     The spring embodiment of the present invention is substantially identical to the cam embodiment. The most important difference between the spring and cam embodiments is the replacement of cam members  204  (see FIG. 6) with leaf springs  226  (see FIG.  7 ). When the spring embodiment of exit tray  102  is in the retracted position, downward-facing surface  228  of frame member  106  applies a downward force on the upper surfaces  230 ,  232  of first and second sheet support members  112 ,  114 , thereby maintaining leaf springs  226  in a compressed state. 
     In the spring embodiment, as exit tray  102  is moved from the retracted position toward the extended position, sheet support member upper surfaces  230 ,  232  begin to clear frame surface  228  and the distal ends  208 ,  212  of first and second sheet support members  112 ,  114  rotate upward due to the upward force generated as leaf springs  226  are relieved from their compressed state. 
     As exit tray  102  is moved from the extended position to the retracted position, a downward force is applied to the upper surfaces  230 , 232  of first and second sheet support members  112 ,  114  so that upper surfaces  230 ,  232  pass beneath frame surface  228 . This downward force can be achieved manually, for example, by the user applying the downward force. The downward force can also be applied by frame surface  228  by selecting a shape of support members  112 ,  114  or frame surface  228  such that contact of the upper surfaces  230 , 232  with frame surface  228  occurs progressively from proximal ends  210 ,  214  to distal ends  208 ,  212  of sheet support members  112 ,  114  as exit tray  102  is moved toward the retracted position. It is within the scope of the present invention to have shallow recesses in base  108 , generally similar to cam recesses  172 ,  174  to accept leaf springs  226  to reduce the downward force to be applied to upper surfaces  230 ,  232  when exit tray  102  is moved from the extended position to the retracted position. 
     FIG. 8 shows a diagrammatic side view of the operation of ink jet printer  100  with the cam embodiment of exit tray  102 . FIG. 9 shows a diagrammatic side view of the operation of ink jet printer  100  with the spring embodiment of exit tray  102 . Structural components common to FIGS. 8 and 9 are referred by corresponding reference numerals. Unless otherwise indicated, the discussion that follows applies to both FIGS. 8 and 9. 
     A sheet of media  116  is transported from an input tray  118  to exit tray  102  by a series of rollers  120 ,  122 , and  124 . As media  116  is being transported, it passes beneath a printhead assembly including a cartridge  126  and a carrier  128 . The cartridge  126  is removably secured to carrier  128  by a spring-loaded latch (not shown). Carrier  128  is reciprocated back and forth along a guide rod  130  by a drive belt (not shown). The drive belt is driven by a motor that is controlled by an electronic control means. The bottom of carrier  128  contains a foot  132  which rides in a groove  134  of guide rail  136 . Both guide rail  136  and guide rod  130  are secured to the side frames (not shown) of printer  100 . A nozzle plate  138  on the bottom of a downwardly extending portion  140  of cartridge  126  contains an array of nozzles (not shown) for ejecting ink droplets in a downward direction, toward media  116 . A trough  142  is provided to collect waste ink droplets. 
     As media  116  passes beneath nozzle plate  138 , nozzle plate  138  along with the rest of the printhead assembly is reciprocated back and forth along guide rod  130 . Ink is ejected from the nozzles in nozzle plate  138  at prescribed transverse locations, to form an image on media  116 . The transverse cross-section of media  116  is generally linear while it is being carried from input tray  118  to exit tray  102 . 
     FIG. 10 shows exit tray  102  in the extended position receiving a sheet of media  116  exiting printer  100 . As media  116  begins to exit printer  100 , the media bends downwardly until media  116  is supported at its right edge  220  by a region of surface  230  near distal end  208  of first sheet support member  112  and at its left edge  222  by a region of surface  232  near distal end  212  of second sheet support member  114 . As long as the trailing end of media  116  is supported within printer  100 , and supported at right and left edges  220 ,  222  by sheet support members  112 ,  114 , media  116  is held generally flat (planar), but with a slight undulation which increases in magnitude from the trailing end of media  116  to the front end of media  116 . Once the trailing end of media  116  is released by printer  100 , media  116  assumes a generally concave shape along its transverse direction due to the support of right and left edges  220 ,  222  and the downward force of gravity on the unsupported regions of media  116 . The central portion of media  116  rests on upper surface  184  of base extension  110 . The concave, transverse cross-section provides increased stiffness to media  116  along its longitudinal axis. Because of the increased stiffness, media  116  can have a longer longitudinal extent than the extent of exit tray  102  in the extended position and still maintain a linear longitudinal cross-section. 
     Since the printed media is retained in exit tray  102  in a concave shape, use of exit tray  102  allows a longer ink drying time for a printed sheet then would be possible in a traditional flat exit tray. Because ink is not usually printed immediately adjacent to left and right transverse edges  220 ,  222  of media  116 , the printed portion  224  of media  116  resting in exit tray  102  is significantly lower than the non-printed edges  220 ,  222 . Thus, a subsequent sheet of media is carried at its transverse edges by first and second sheet support members  112 ,  114  above the printed portion  224  of media  116 . Until released by printer  100 , the transverse cross-section of the subsequent sheet of media is generally linear and, therefore, printed region  224  of media  116  is not contacted by the subsequent sheet until the subsequent sheet is released by printer  100 , thereby permitting an extended drying time for the printed portion  224  of media  116 . 
     The exemplifications set forth herein illustrate preferred embodiments of the invention and should not be construed as limiting the scope of the invention. Although the invention has been described in detail with reference to certain preferred embodiments, those skilled in the art will recognize that variations and modifications exist within the scope and spirit of the present invention as described and defined in the following claims.