Abstract:
An auxiliary print media tray or cartridge forms part of a print media handling system that provides for holding two discrete supplies of print media in a manner that permits the user to select printing media from one supply or another, without the need for first emptying either of the supplies. The print media is oriented in a manner such that both supplies engage a common media feed mechanism, such as pick and feed rollers. As a result, a printer that employs two discrete media supplies is provided without the increased manufacturing cost or size that would otherwise be required if duplicate pick and feed rollers (or related components) were employed. One embodiment of the present invention is particularly adapted for holding in an auxiliary tray a supply of relatively small print media, such as photo-type paper that is popular as a medium upon which high-quality digital images may be printed.

Description:
TECHNICAL FIELD 
     This invention relates generally to a system for handling print media in a printer, and more particularly to an auxiliary tray that enables the system to efficiently support and use a selected one of two discrete supplies of print media that are stored in a printer. 
     BACKGROUND AND SUMMARY OF THE INVENTION 
     Printers have trays or drawers that hold a supply of print media, such as paper, in a location where the paper can be brought into engagement with a printer feed mechanism. The feed mechanism contacts the top sheet of the paper supply and advances that sheet into the printer. These feed mechanisms are often referred to as “pick and feed” rollers. From the pick and feed roller, the media sheet is moved into a print zone where an image or text is printed on the sheet. 
     The supply trays (also known as “input” trays) normally accommodate different sizes of print media. To this end, adjustable guides are built into the input trays to ensure that whatever size paper is provided, it is advanced uniformly (that is, without undesirable skewing) into the printer. 
     With input trays that are adaptable to handle various sizes of paper, the user is required to remove the existing supply of paper from the tray before adding the different-sized media. This slows the printing operation and, because of the effort required to swap media sizes in this manner, a user may be unwilling to print on different sizes of media. 
     Some printers are equipped with slots or the like for feeding single sheets of media into a feed mechanism without the need for removing the input tray. This approach, however, does not provide a means for storing in the printer an alternate supply of media that can be selectively fed to a common feed mechanism. 
     Some printers are provided with more than one input tray, and this arrangement greatly reduces the effort needed to switch printing between different sizes of print media. In the past, however, this duplication of input trays has also led to the duplication of many of the mechanisms for delivering the media to the print zone. Conventional printer designs that use more than one input tray require additional sets of pick and feed rollers or the like to direct to one location (the print zone) sheets of media entering the printer from two different locations. Such relatively complicated media handling systems add to the manufacturing cost and, usually, to the size of the printer. 
     This invention is directed to a print media handling system that holds two discrete supplies of print media in a manner that permits the user to select for printing a sheet of media from one supply or another, without the need for emptying either of the supplies. Moreover, the print media is held and moved in a manner such that both supplies engage a common feed mechanism, such as pick and feed rollers. As a result, a printer that employs two discrete media supplies is provided without the increased manufacturing cost or size that would otherwise be required if duplicate pick and feed rollers (or related components) were employed. 
     A preferred embodiment of the present invention is particularly adapted for holding in an auxiliary tray a supply of relatively small print media, such as the photo paper (in the range of 10 centimeters by 15 centimeters, for example) that is popular as a medium upon which high-quality digital images may be printed. 
     The tray is maintained in a retracted position until the user wishes to print on the media that is held in the tray. The tray is then manually moved by fingertip control of the user. This movement places the leading edge of the media into the “pick zone” of the printer, in which zone the pick rollers can contact the media and advance it into the printer. Once that print task is complete, the user, using fingertip control, retracts the tray so that the media it carries is no longer in the pick zone. 
     Whenever the tray is in the retracted position, print media in the other input tray (hereafter referred to as a drawer) is exposed in the pick zone. Thus, the user need not make any adjustment to this drawer in order to recommence its use after the tray is retracted. The next print command will cause the printer&#39;s pick and feed rollers to engage the media in the drawer. One can appreciate, therefore, that the present invention provides the convenience of a two-tray system, without the complexity of a system requiring pick and feed rollers or other feed mechanisms dedicated to each of the drawer and tray. 
     A number of other inventive aspects are provided. For instance, a movable stop is used to ensure proper loading of media into the auxiliary tray, but without interfering with the removal of the media from the tray by the pick and feed rollers. 
     Also provided is a sensor for generating a signal when the auxiliary tray is moved toward the position where the media it carries is in the pick zone. Among other things, this signal (which is fed to the printer controller) prevents damage to the printer or media in the event the user attempts to move the tray toward the pick and feed rollers while those rollers are engaging media in the drawer. 
     Useful mechanisms are also provided for controlling the position of the tray relative to the printer, and for properly locating different sizes of media in the auxiliary tray. 
     Other advantages and features of the present invention will become clear upon study of the following portion of this specification and the drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a portion of a printer that is adapted to use a media handling system that incorporates the auxiliary tray of the present invention. 
     FIG. 2 is a diagram showing in side cross-section a media input drawer and movable auxiliary tray made and used in accordance with the present invention. 
     FIG. 3 is a top plan view showing the primary components of the present invention, including a base and slidable auxiliary tray, the tray shown in a retracted position so that media carried by the tray is away from the printer&#39;s pick rollers. 
     FIG. 4 is a top view, like FIG. 3, but showing the auxiliary tray moved into an extended position so that media carried by the tray is in a position for engagement by the printer&#39;s pick rollers. 
     FIG. 5 is a detail view of a spring used to secure the tray in the retracted position. 
     FIG. 6 is an enlarged side view of the auxiliary tray of the present invention. 
     FIG. 7 is a top plan view, like FIG. 3, but showing a cover for the tray in place. 
     FIG. 8 is a top plan view, like FIG. 7, but also showing a hinged cover in place. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Before turning to the particulars of preferred embodiments, it is noted that the for the purposes of this description the term “print media” is intended to include cut-sheet paper of any weight, photo-grade paper (or “photo media”), transparencies, envelopes, banners, rolled media, etc. Also, although the preferred embodiment of the invention is adapted for a printer, it is contemplated that the present invention is also useable with many other hard copy devices, of ink-jet or laser type, including copiers, facsimile machines, and scanners. 
     In FIG. 1 there is shown a portion of a chassis  20  of a printer with which the present invention may be incorporated. Many of the printer components that are irrelevant to this description are omitted from the figure for clarity of illustration. 
     The chassis  20  includes a bottom plate  22  and two spaced-apart side walls  24 . The side walls  24  support a rotatable shaft  26  that carries a group of pick and feed rollers  28  (hereafter referred to as rollers). The shaft is driven to rotate the rollers  28  in the direction shown by arrow  30  to advance print media, such as paper, one sheet at a time into the printer for receiving the printed image or text. 
     The rollers  28  have rubber or rubber-like outer surfaces that frictionally engage the top sheet of a supply of paper. A removable drawer  32  that slides into the printer carries one supply of paper, which can be thought of as a main supply. 
     In a preferred embodiment, the drawer  32  includes a generally flat bottom  34  and opposing side walls  36  that project upwardly therefrom. The inner end of the drawer  32  includes an inner wall  38 . The length of the supply of paper carried by the drawer (the paper not shown in FIG. 1) fits between the inner wall  38  and a length guide  40  that projects from the bottom of the drawer and can slide toward and away from the inner wall to accommodate paper of various lengths. The width of the supply of paper carried by the drawer fits between one side wall  36  and a width guide  42  that projects from the bottom of the drawer and can slide toward and away from the side wall to accommodate paper of various widths. 
     The paper-filled drawer  32  fits snugly between opposing vertical surfaces  46  of a pair of brackets  48  located at the junction of the chassis bottom plate  22  and each chassis side wall  24 . Only one bracket  48  is visible in FIG.  1 . The drawer  32  is slid into the printer in the direction shown by arrow  44 . When the drawer is fully inserted (see FIG. 2) its inner end  37  resides adjacent to the lowermost parts of the rollers  28 . 
     When considering the drawer  32  fully inserted (FIG.  2 ), the space between the inner end  37  of the drawer and the rollers  28  can be thought of as a pick zone  50 . When paper is not being fed into the printer, the distance between the top sheet of paper  52  in the drawer and the nearest part of the rollers  28  represents a dimension of the zone. The arced arrow  54  shows this distance. For clarity, only a single sheet of paper  52  is shown (dashed lines) in FIG.  2 . It will be appreciated that the drawer may be initially filled with a stack of paper that fills the tray to the top of the inner wall  38 . 
     The operation for moving or “picking” a top sheet of paper from the drawer occurs when the paper is brought into contact with one or more (at least two) rotating rollers  28 . That is, the distance “D” between the roller and paper is eliminated, at least temporarily. In this regard, one of ordinary skill will appreciate that the distance “D” can be eliminated by lowering the rollers  28  to the paper or visa versa. (Alternatively, a selectively drivable roller set could be arranged to permanently rest on the top sheet of paper -yielding upwardly as the tray is removed, refilled, and replaced- and driven only when a paper feed operation is initiated.) 
     In a preferred embodiment, the distance “D” is eliminated by moving the paper  52  to the rollers  28 . To this end, the drawer is equipped with a pressure plate  56  that lines the bottom  34  of the drawer at about the innermost one-third of the drawer. The pressure plate  56  is hinged, such as shown at  60 , on the side away from the drawer inner end  37  so that the plate may be rotated, as shown in dashed lines of FIG. 2, toward the rollers  28  to bring the paper  52  into contact with the rotating rollers  28 . For illustration, the plate  56  is shown rotated upwardly in FIG.  1 . 
     The pressure plate is formed with a thin ramp  62  that is flush with the surface of the plate  56  near the hinged edge and gradually rises above the surface in the direction toward the inner end  37  of the drawer. The ramp is at its thickest (about 1.5 mm) at the inner end and there underlies a roller  28 . In a preferred embodiment a wear surface  64  (FIG.  1 ), such as cork, is inlaid into the thickest part of the ramp  62 . It will be appreciated that the wear surface  64 , raised as it is above the remainder of the pressure plate surface, is the only portion of the plate that may be exposed for direct contact with a roller  28  when the plate is rotated toward the rollers. 
     Any of a number of mechanisms may be used to rotate or “lift” the pressure plate  56  toward the rollers  28 . In the depicted embodiment, a pivotal actuator plate  66  is provided in the bottom plate  22  of the of the printer chassis (FIGS.  1  and  2 ). The actuator plate  66  is sized to fit through a clearance notch  68  (FIG. 1) formed in the bottom  34  of the drawer, generally underlying the ramp  62 . The actuator plate  66  is driven by the printer controller to lift the pressure plate toward the roller as shown in dashed lines of FIG.  2 . 
     As noted, the just-described drawer  32  and associated mechanisms can be considered the main paper supply for the printer. For instance, a user may prefer to hold in the drawer, ready for printing, standard sized paper. In accord with another aspect of this invention, there is also provided an auxiliary tray and associated mechanisms for holding another supply of print media, which supply can be moved by the user into and out of the pick zone so that the auxiliary supply of print media is used in lieu of the main supply. That is, the main supply will be used by default if the auxiliary supply is not moved into the pick zone. This description now turns to the auxiliary tray with initial reference to FIGS. 2-4. 
     The auxiliary tray  70  (hereafter, simply “tray”) is, like most of the components herein described, formed of injection molded plastic and is generally rectangular in shape as viewed in plan (FIG.  3 ). (For clarity, only a dashed in portion of the drawer  32  is shown in FIGS. 3 and 4.) The tray is supported for sliding movement by a base  72 , which is a generally planar member (except for some upwardly extending walls etc., as described below) that is fastened to and spans between the horizontal surfaces  74  of the above described brackets  48  (FIG.  1 ). The base  72  holds the tray  70  above the drawer, so that both a media-loaded drawer and a media-loaded tray are simultaneously in the printer, and one need not be swapped for the other. 
     With reference to FIG. 4, the tray  70  fits between a pair of guide walls  74 ,  76  that extend upwardly from the flat base plate  78  of the base  72 . The tray  70  also extends across a generally rectangular opening  80  in the base plate  78 . The underside edges of the tray  70  rest on opposing shelves  80 ,  82  that project horizontally (i.e., in the plane of FIG. 4) under the sides of the tray. The tray  70  slides along these shelves, as will be discussed more below. 
     In FIG. 3, the tray  70  is depicted in a retracted position. In this regard, the tray includes an outer wall  84  that projects upwardly from the smooth, flat media-support surface  86  of the tray. That outer wall  84  abuts a forward one  88  of two base walls  88 ,  90  that extend upwardly from the base plate  78  (FIG.  4 ). 
     A finger pad  92  is formed on the tray  70  to extend from the center of the tray outer wall  84 . In the retracted position of the tray, the pad extends over the forward base wall  88  and through a notch formed in the rearward base wall  90 . As best seen in FIG. 6, the finger pad  92  has a ribbed upper surface. The inner one-half of the ribbed surface is atop a movable button part  94  that extends through a small housing underlying the pad  92  and terminates in a hooked end  96 . The button part  94  is spring-biased upwardly. The hooked end  96  of the button part is beveled so that as the tray is moved into the retracted position, the beveled end contacts and slips under a retainer bar  98  that protrudes from the underside of the base plate  78 . The button part thereafter snaps back (as a result of the spring bias) to latch onto the retainer bar  98  (FIG.  2 ). 
     The user easily moves the tray into the retracted position by single-finger  100  manipulation of the pad  92 . To move the tray out of the retracted position, as explained more below, the user depresses the button part  94  and slides the tray forward, releasing pressure on the button once the hooked end  96  has cleared the retainer bar  98 . 
     In addition to the just described latch mechanism, a detent means is provided to resist inadvertent movement of the tray  70  out of the retracted position. This detent means is preferably embodied in a flat, metal spring  102  as shown best in FIG.  3  and the detail of FIG.  5 . One end  104  of the spring is made into a reversed “Z” shape and wedged against bosses  106  formed to project into the narrow space between the base guide wall  76  and a parallel support wall  108 . The free end of the spring  102  is formed into a “V” shape, the apex  110  of which protrudes through a notch  112  in the guide wall  76 . 
     While the tray is in the retracted position, the apex  110  of the spring fits into a correspondingly shaped groove  114  (see FIGS. 3 and 4) in the outer, right side wall  116  of the tray. The spring yields when the tray is moved out of the retracted position, and the apex  110  rides along the wall  116 . 
     The tray  70  can be loaded with print media while in the retracted position (FIGS.  3  and  7 ). Media, such as photo-type print media that is sized, for example, to be 15 centimeters long and 10 centimeters wide, is slipped across the media-support surface  86  toward the leading edge  144  of the tray (in the direction from the top to the bottom of FIG.  3 ). This photo media is shown in the fully loaded position as the dashed lines  120  in FIG.  3 . 
     As the media  120  is advanced to the fully loaded position, its leading edge  122  (here, for simplicity, considering only a single sheet of media  120 ) passes under a lip  124  that protrudes over the tray surface  86  from the uppermost edge of an inside, right wall  126  of the tray (see FIG.  2 ). Across from the lip  124 , the media  120  also passes between two spaced-apart blades  130 ,  132  of a cleaver-shaped justification lever  134 . The lower blade  132  of the lever is flush with the tray surface  86 , fitting into a suitably shaped clearance opening  135  made through that surface. That opening  135  is sized to allow some pivotal movement of the lever as described next. 
     The justification lever  134  is pivotally mounted to a post that is carried on the tray. The lever is urged by a spring  136  toward the inside right wall  126  of the tray. The spring  136  is carried by the tray and attached thereto (wedged between bosses) in a manner substantially identical to that described with respect to the detent spring  102 . The free end of the spring  136  bears against the lever  134 . The spring end  136  yields when relatively wide media is slipped between the lever blades  130 , 132  so that the lever can pivot (counterclockwise in FIG. 3) to accommodate the wider paper yet still press that media against the side of the tray to justify it and to help ensure the media does not move relative to the tray as the tray is extended and retracted. 
     Another lip  140  (see FIG. 4) is formed in the tray  70  on the left side thereof. That lip  140  protrudes over the tray surface  86  from the uppermost edge of an inside, left side wall  142  that extends upwardly from the tray surface  86  and part way back from the leading edge  144  of the tray. The media  120  slips under this lip  140  when loaded. 
     As best shown in FIG. 3, a generally “S” shaped stop  150  is provided. The stop is pivotally mounted to the base plate  78  and includes a head that comprises two spaced-apart blades  152 , 154 . The leading edge  122  of the media fits between these blades and abuts a vertical stop wall  156  that is recessed between the blades. This abutment limits the distance that the media  120  may be inserted into the tray  70  while the tray is in the retracted position. 
     In a preferred embodiment, the distance between the lever blades  130 ,  134 , and the distance between each lip  124 , 140  and the tray surface  86 , and the distance between the stop head blades  154 , 154 , matches the maximum thickness of media to be loaded into the tray  70 . In a preferred embodiment, this thickness is about 7 mm, to hold at least  24  sheets of photo media. 
     When the tray  70  is retracted, a cylindrical post  160 , which is formed on the end of an arm that protrudes from the tray side wall  142 , nests in a correspondingly shaped curve  162  formed in the stop. The curve  162  and post  160  are configured and arranged to prevent the stop  150  from pivoting (counterclockwise) while the tray is in the retracted position. As a result, the stop wall  156  remains in place to serve as a limit for the loaded media, as described earlier. (As will be seen, the stop moves out of this location when the tray is extended). With the tray in the retracted position, clockwise rotation of the stop  150  out of the stop location shown in FIG. 3 is limited by an abutment  168  that protrudes from the base plate  78  to abut a flattened part  170  on the stop. 
     A sensor  172  is carried on the base plate  78 . A link  176  is rotatably mounted to the base plate  78  near the sensor. The link includes a pair of legs, one of which  180  terminates in a foot  182  (see FIG. 4) that fits into the sensor  172  while the tray is in the retracted position (FIG.  3 ). Specifically, the preferred sensor  172  is an optical type and the foot  182  fits within a slot between the emitter and detector of that sensor. 
     The other leg of the link  176  has a contact surface  186  along which rides the rounded end of a sensor arm  188  that is formed with and moves with the tray  70  as the tray is extended and retracted. Referring to FIG. 3, it can be appreciated that in moving out of the retracted position and before reaching the extended position, the tray&#39;s sensor arm  188  encounters a part of the contact surface  186  that crosses the linear path traveled by the sensor arm. As a result, the link  176  is rotated counterclockwise by an amount sufficient to pull the foot  182  from between the emitter and detector of the sensor  172 . A corresponding output signal (i.e., representing the movement of the tray toward the extended position) is thus provided by the sensor to the printer controller (not shown). It will be appreciated that the sensor output signal is useful, for example, to halt feeding media from the drawer  32  to prevent damage to the printer or media in the event the user attempts to move the tray  70  toward the rollers  28  while those rollers are engaging media in the drawer. 
     With respect to FIG. 4, as a user wishing to print onto the media carried in the tray  70  moves the tray to the extended position, the above-described post  160  on the tray rides along the facing vertical surface of the stop  150 . This has a camming effect on the stop  150  to rotate the stop counterclockwise so that the stop wall  156  in the head of the stop swings away to permit the leading edge  122  of the media to move inwardly, toward the pick zone  50  (FIG.  2 ). This counterclockwise rotation of the stop  150  is limited by the abutment of a tail  190  on the stop with an intermediate base wall  192 . 
     The cylindrical post  160  of the tray fits against a curve  163  (see FIG. 3) in the stop  150  when the tray is in the extended position (FIG.  4 ). Inasmuch as the stop, in this position, is limited against further counterclockwise rotation, the fit of the post  160  and curve  163  functions to prevent the extended tray from moving out of its position (that is, preventing skew of the tray relative to the base). 
     The length of the tray  70  between the outer wall  84  and leading edge  144  is selected to be slightly shorter than the shortest media that is to be carried by the tray. This ensures that, in the extended position, the media, and not the leading edge of the tray, contacts the adjacent rollers  28 . 
     With reference to FIG. 6, the tray includes guide rails  200  having undersides  202  that rest on the above described shelves  80 ,  82  of the base. The underside  202  appearing in FIG. 6 rests on one shelf  80 . A similarly shaped rail underside is provided on the opposite side of the tray (not shown), and the following portion of the description applies to the rails on both sides of the tray. 
     The rail underside  202  is inclined such that as the tray is slid toward the extended position (moved to the left in FIGS. 2 and 6) the innermost part  203  of the underside  202  will slip off and move slightly beneath the innermost edge  204  of the base plate (where that edge meets the shelf  80 ) by an distance “X” (FIG. 6) so that the leading edge  144  of the tray, hence, the leading edge of the media  122 , is directed toward the wear surface  64  of the ramp  62  to a location such that the leading edge of the media will not contact the rollers  28  unless lifted into such contact by the movement of the above-described pressure plate  56 . 
     So located, the leading edge  144  of the tray  70  is lifted with the pressure plate  56  when paper is to be picked by the rollers  28 . In this regard, it is noteworthy that the extended tray  70  is mounted to permit sufficient rotation about its outer wall  84  to permit this lifting motion. This rotation movement of the tray is accomplished in part via sufficient tolerance in the pivotal mounting of the stop  150 , which stop is lifted slightly with the tray about an axis generally perpendicular to its pivot axis. In short, the stop pivot connection is loose enough to let the stop move with the tray, rather than impeding that motion. 
     FIG. 7 shows the present media handling system with a cover  210  that is fixed in place. The cover edge fits under tabs  212  on the base. The cover  210  also includes a number of prongs (not shown) that extend from the underside of the cover to engage mating openings in the base plate  78  to hold the cover in place. The cover conceals the base plate  78  and tray mechanisms but for a window  214  formed in the cover to overlay the outer end of the tray  70  when the tray is retracted. The media supply in the tray may be replenished by inserting the media through the window  214 , sliding it into the tray  70 . 
     To facilitate removal of media from the tray, the window  214  is provided with a corner enlargement  216  that aligns with a finger hole  218  made through the surface  86  of the tray. The finger hole enables the user easily to remove the media by lifting the edge or undersides of the media in the tray. 
     The cover  210  is also provided with an envelope slit  220  to permit a user to manually insert an envelope therethrough so that the edge of the envelop engages the rollers  28 . 
     FIG. 8 shows the present media handling system with a movable cover  222  in place. That cover  222  is hinged as shown at  224  so that a user may move it from the closed position (FIG. 8) to expose the loading window  214  (see FIG.  7 ). In the closed position, nearly all of the outer end of the base  72  is covered except for an elongated slot  226  in which moves the exposed finger pad  92  as the tray is slid between the extended and retracted position. Thus, when the tray  70  is loaded with the media desired by the user, the user need not lift the cover  222  to move the tray into and out of the extended position. 
     Although a preferred embodiment of the system and its components have been described, it will be appreciated by one of ordinary skill that the spirit and scope of the invention is not limited to those embodiments, but extend to the various modifications and equivalents as defined in the appended claims. For example, the movement of the tray  70  into and out of the extended and retracted position may be carried out by actuators driven by the printer controller, thereby eliminating the need for the user to manipulate the tray. 
     Also, the tray could be embodied as a separate drawer or cartridge that is configured to be installed with the main supply drawer (thus using the same feed mechanism) in instances where, for example, one wished to employ a photo media cartridge that would be replaceable with another cartridge carrying other media, such as envelopes, index cards, etc.