Abstract:
Techniques are disclosed for supporting objects in a tray and moving different portions of the objects at different rates for inputting or outputting from an objects processor. These techniques may be applied to stacking objects that has a thickness at one end greater than the thickness at another end, for example, resulting in stacking height of the thicker end increasing faster than the stacking height of the other thinner end.

Description:
BACKGROUND 
   Machines that process stacked objects and output the processed items also in a stack are common. For example, printing industry systems commonly stack blank recording mediums and feed them into printing processors and stack printed outputs. This type of stacking/processing/stacking sequence may also be found in common office equipment such as xerographic copiers or printers. 
   SUMMARY 
   Techniques are disclosed for supporting objects in a tray and moving different portions of the supported objects at different rates for inputting to or outputting from an objects processor. These techniques may be applied to stacking objects that has a thickness at one portion greater than the thickness at another portion, for example, resulting in stacking height of the thicker portion increasing faster than the stacking height of the other thinner portion. In xerographic printing or copying systems, for example, these techniques provide support for stacking recording mediums in a tray that accommodates the variation of stacking heights so that a particular desirable relationship between the recording medium on top of the stack may be maintained with respect to a feeder mechanism that either removes recording mediums from the stack and inputting them into a printer or copier, or receiving the recording mediums from the printer or copier and stacking them in a thickness variable accommodating manner. 
   A particular implementation provides an arm having a free end and a pivot end for moving different portions of stacked recording mediums at different rates. The free end may be provided with an appropriate surface shape to support the recording medium while the pivot may be provided with a structure that allows the arm to slide and rotate on a pivot guide, for example. The recording medium support may rest, on a tray lift so that as the tray lift moves up and down, different portions of recording mediums stacked above the support may be moved at different rates. 
   Multiple pivot points may also be used so that an arm may pivot about a pivot support at one of two ends and pivot about a second pivot support at an intermediate point between the two ends so that rotational movement may be controlled relative to a separate recording medium support surface. Other techniques may be used such as different size gears and racks attached either to the support for recording mediums or the frame of the tray so that different portions of the support for the recording medium may be moved at different rates. Multiple arms could also be used to adjust movement rates at different portions of the support for the recording medium. 
   Using the various techniques discussed above, documents having non-uniform thicknesses such as docucards, for example, may be stacked in a tray so that the uppermost recording medium may be maintained at a particular position for proper feeding of the recording medium into a processor such as a printer or to accept processed recording mediums into a stacker. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Various disclosed exemplary embodiments of the systems and methods will be described in detail, with reference to the following figures, wherein: 
       FIG. 1  shows an example of a feed tray coupled to a processing machine; 
       FIG. 2  shows an example of an object to be processed such as a docucard; 
       FIG. 3  shows an exemplary profile of the docucard; 
       FIG. 4  shows an exemplary stack of docucards; 
       FIG. 5  shows an exemplary docucard feed tray; 
       FIG. 6  shows an exemplary top view of the arm shown in  FIG. 5 ; 
       FIG. 7  shows an exemplary stacker tray; 
       FIG. 8  shows the stacker tray having a stack of docucards, as an example; 
       FIG. 9  shows the stacker tray stacked with a maximum number of docucards; 
       FIG. 10  shows a perspective view of a specific arm for the stacker tray; 
       FIG. 11  shows an exemplary stacker tray for stacking documents having a thicker corner such as stapled documents; and 
       FIG. 12  shows an exemplary top view of the stacker tray shown in  FIG. 11 . 
   

   DETAILED DESCRIPTION OF EMBODIMENTS 
   As discussed above, many types of machines process objects that are stacked in an input tray, and each object of the stack may be input into the processing machine, processed and output to an output stacker. For ease of discussion, a print machine such as a xerographic copier or printer is used as an example to illustrate various features related to the input and output trays. 
     FIG. 1  shows an exemplary diagram of an office device such as a xerographic printer  100  that may include a feed tray  102 , a feeder  110  and a print machine  108 . The feed tray includes a tray lift  106  that may be guided by a lift guide  114 . Recording medium  104  may be stacked above the tray lift and moved in a substantially linear movement directions  116 . 
   Recording medium  104  may have substantially uniform thickness and tray lift  106  lifts the stack of recording mediums  104  upwards so that a belt assembly  112 , for example, of feeder  110  may separate a top recording medium from the stack and feed the top recording medium into print machine  108  for processing. 
   Feed tray  102  shown in  FIG. 1  may be efficient for recording mediums  104  that have substantially uniform thickness. However, if the thickness distribution of the recording medium is not substantially uniform, then the interaction between the top recording medium and belt assembly  112  may become complicated and may result in various difficulties such as misfeeds, etc. Although interface requirements between the top recording medium and belt assembly  112  may vary depending on different types of feeding mechanisms, it is usually a requirement that the top surface of the top recording medium is substantially parallel to (or flat relative to) a bottom surface of belt assembly  112  so that sufficient contact may be provided between belt assembly  112  and the top surface of the top recording medium to achieve the feeding process. In addition, a leading edge of the top recording medium usually must be aligned with an input port of the print machine  108  to achieve successful feeds. Thus, when recording medium  104  is thicker at one end than at other portions, the top surface of the top recording medium of a stack of such recording mediums may have one end that is substantially closer to belt assembly  112  than its remaining portion due to accumulated thicknesses of the complete stack of recording mediums. 
   Docucard is an example of such a document having non-uniform thicknesses across its surface. As shown in  FIG. 2 , a docucard recording medium  118  may include cards  120  such as plastic credit cards mounted at particular positions on a substrate  119  such as paper, for example. When placed into a tray, docucard  118  may be fed by belt assembly  112  into print machine  108  in a direction  122  as indicated by the arrow. 
     FIG. 3  shows an exemplary profile of docucard  118 . Cards  120  have thicknesses that are comparable if not greater than the thickness of substrate  119 . Thus, when stacked as shown in  FIG. 4 , the portion of docucards  118  that include cards  120  may stack to a thickness “a” while portions that do not include cards  120  may stack to a thickness “b,” and a&gt;b. Thus, when docucards  118  are placed into a feed tray such as feed tray  102 , the stacking height on one side would be much greater than the stacking height on the other side. The top surface of the top docucard would contact belt assembly  112  in a non-uniform way and the leading edge of the docucard that feeds into print machine  108  would also be improperly aligned causing feeding errors, for example. 
     FIG. 5  shows an exemplary view from a direction  124  of feed tray  102 . The feed tray  102  may be fitted with an arm  126  and a spacer  136  so that recording mediums with non-uniform thicknesses such as docucards  118  may be stacked to maintain a desirable relationship between the top recording medium, belt assembly  112  and input port of print machine  108 . Arm  126  may include a pivot  132  at one end and a recording medium support  134  at the other end. Pivot  132  may be coupled to a pivot guide  130  that may be supported on a pivot guide support  128 . A free end of recording medium support  134  may rest on spacer  136 . Spacer  136  and pivot guide  130  are dimensioned to maintain the top recording medium in a desired position relative to belt assembly  112 . Spacer  136  may be supported by tray lift  106  so that spacer  136  and arm  126  move in response to the movement of tray lift  106 . 
   Pivot  132  permits arm  126  to move angularly as well as translationally. As tray lift  106  moves downward, the free end of recording medium support  134  follows the downward movement and arm  126  rotates about pivot  132 . However, the contact between arm  126  and spacer  136  remain substantially in the same position as tray lift  106  moves downward thus causing pivot  132  to slide, guided by pivot guide  130 . As shown, pivot guide  130  may cause pivot  132  to move through an arbitrary curve so that recording medium support  134  may maintain a desired position to support the recording medium so that the top recording medium may maintain a desired position relative to belt assembly  112  of feeder  110 . 
   Pivot guide  130  may be a slot and pivot  132  may be a pin inserted into the slot of pivot guide  130 . As tray lift  106  moves downward, arm  126  angularly rotates about pivot  132  and pivot  132  slides in the slot of pivot guide  130  thus adjusting the position of recording medium support  134 . Pivot guide  130  may also be a cam riding surface and pivot  132  may be a cam sliding down the cam riding surface of pivot guide  130 . Pivot  132  may be held to the cam riding surface by the weight of arm  126 . Arm  126  and spacer  136  may be disposed in feed tray  102  as an insert so that feed tray  102  that is normally used to feed recording medium  104  of uniform thickness may be quickly adapted for feeding recording medium of non-uniform thickness such as docucards  118  by simply inserting spacer  136  and arm  126 . 
     FIG. 6  shows a top view of arm  126 . Recording medium support  134  may have a shape that corresponds to the shape of the recording medium such as docucard  118 . The length of arm  126  may be adjusted as required depending on thickness variations of the recording medium. Pivot  132  may be disposed at edges of an end of arm  126 , as shown in  FIG. 6 , and pivot support  130  may be a slot or cam surface or other guide mechanisms to control the position of pivot  132  to achieve proper positioning of arm  126  relative to feeder  110  and print machine  108 . 
   While the above discussion used printer machine  108  and docucard  118  as examples, arm  126  and spacer  136  may be used in feeder applications of other types of machines. Arm  126  may provide variations in movement of recording medium support  134  (or object support) so that different portions of the recording medium (or object) may be stacked at different heights depending on a number of the recording mediums (or objects) that are stacked. In the docucard example, substantially linear movement in directions  116  of the card end of docucard  118  is greater than the opposite end that does not include cards  120 . Thus, the greater stacking height required to accommodate the card thickness is accommodated so that the recording medium on top of the stack is maintained at a controlled relationship with respect to feeder  110  and print machine  108 . 
     FIG. 7  shows a stacker  200  for receiving outputs of machines such as printer machine  108 . Stacker  200  may include a feeder  210  and a stacker tray  202 . Feeder  210  may receive printed recording mediums (or objects) and feed them into stacker tray  202  using devices such as belt assemblies  212 . Stacker tray  202  may include a stacker lift  206 , a recording medium guide  222 , which may include a guide surface  224 , and an arm stop  216 . Similar to feed tray  102 , stacker tray  202  may include an arm  226  that pivots around a pivot  232  disposed at one end of arm  226  and include an arm glide  211  that rides on stacker lift  206 . Arm  226  also may include a support spring  208  that flexibly support the recording mediums as they are stacked in stacker tray  202 . 
   Stacker lift  206  may include an arm positioner  209  disposed to position arm  226  so that the recording mediums that are fed from feeder  210  may be properly received onto arm  226 . As recording mediums are fed into stacker tray  202 , stacker lift  206  may move downward. Initially, arm  226  may follow stacker lift  206  vertically because pivot guide  230  may be shaped into a vertical slot so that pivot  232  simply glides vertically downward without pivoting arm  226  to have an angular motion. However, when pivot  232  reaches a bottom portion of pivot guide  230 , arm  226  may begin to rotate about pivot  232  and arm guide  211  may begin to slide against a top surface of stacker lift  206 . 
     FIG. 7  shows an intermediate position of arm  226  and a lowest position of arm  226  where arm glide  211  is prevented from gliding further by arm stop  216 . The lowest position of arm  226  may be determined based on maximum weight that can be accommodated or that can be safely removed from the stacker  202 , for example. 
     FIG. 8  shows stacker tray  202  with arm  226  in an intermediate position and recording mediums such as docucards  118  stacked above arm  226 . As shown, the left edges of docucards  118  are pressed against guide surface  224  of recording medium guide  222 . Additionally, support spring  208  may be bent downwards allowing docucards  118  to be gently lowered into a rest position above arm  226 . 
   Guide surface  224  may be formed to have a convenient shape such as the curve shown in  FIG. 8 . As shown, docucards laying above arm  226  are forced into a desirable alignment so that when removed, docucards  118  may be in a desirable stacked position ready for further processing. 
     FIG. 9  shows arm  226  in its lowest position with arm glide  211  pressed against arm stop  216 . Support spring  208  is pressed by the weight of docucards  118  and bent almost against the main body of arm  226 . 
     FIG. 10  shows a specific configuration of arm  226 . Pivot  232  may be formed by a bend of one end of arm  226  and at the opposite end of arm  226 , arm glide  211  may be another bend of the arm  226  or any device that may be used to provide a suitable glide surface such as represented in  FIG. 10 . Arm glide  211  may be rollers or suitable round surfaces for gliding on the top surface of stacker lift  206 . Support spring  208  may have two portions as shown in  FIG. 10  having a bend at the free ends to stiffen the outer edge of support spring  208 . Support spring  208  may be mounted onto the main body of arm  226  using a plate  234  and fasteners via fastener holes  236 . Additionally, a cover plate  238  may be disposed over the plate  234  covering portions of support spring  208  near its attachment end to protect support spring  208  and to provide a smooth surface for recording mediums such as docucards  118  to lay on top of arm  226  and spring  208 . The cover plate  238  may extend toward the free ends of support spring  208 , past the vertical edge of the main body of arm  226  to prevent the recording mediums such as docucards  118  from tipping in the arm  226  and causing a jam or miss-registration in the print machine  108 , for example. 
   While the above examples related to objects such as docucards  118 , objects may have other properties that may cause non-uniform thickness across the surface. For example, transparencies may have a tab on one edge that is of different thickness than other portions of the transparency. Thus, when transparencies are stacked in feed tray  102  or stacker tray  202 , one edge of the transparency stacks higher than the opposing edge causing possible feed difficulties. However, if arm  126  and spacer  136  are used as shown in  FIG. 5 , the top surface of the top transparency may be maintained in a desirable position relative to feeder  110  for proper feeding. Similarly, stacker tray  202  may be used to accommodate printed transparencies. 
   Non-uniform thickness of processed recording mediums may be introduced by the recording medium processor itself. For example, a printer machine or a copier machine may provide a staple option where multiple processed recording mediums may be stapled together at the top left corner, for example. When such stapled documents are stacked in a stacker tray, the stapled corner of the recording mediums stack higher than other portions of the stapled recording mediums thus limiting a number of stapled documents that may be received by a stacker tray before stacking difficulties are introduced. 
     FIGS. 11 and 12  show an exemplary arm  326  that may be configured to accommodate non-uniform thickness limited to a particular portion such as a stapled corner of a recording medium.  FIG. 11  shows a stacker tray  300  that may include stacker lift  306 , spacer  302 , arm  326 , which may include pivots  312  and  332 , and a recording medium support  314 . Pivot  332  may be guided by pivot guide  330  and pivot  312 , at a reference position  313 , may be disposed in a fixed position relative to spacer  302 . For clarity, only the above-noted portions of stacker tray  300  are shown without showing other portions that may be similar to that discussed above and shown in  FIGS. 7-10 . 
   When stacker lift  306  is at its uppermost position, arm  326  may be at a position represented by the dotted version of arm  326 . As stacker lift  306  moves downward, arm  326  rotates about pivot  332  and pivot  312  so that recording medium support moves downward at a faster rate than top surface of spacer  302 . The rate of movement of recording medium support  314  may be adjusted by positioning pivots  312  and  332  and adjusting lengths of arm  326  between pivots  312  and  332  as well as length of recording medium support  314  from pivot  312 . 
     FIG. 12  shows a top view of stacker tray  300 . The spacer  302  has a top surface with an opening forming one corner of the top surface. The recording medium support  314  is shaped to fit the corner of the top surface. Assuming for discussion that the recording medium is approximately the size of the top surface of spacer  302 , recording medium support  314  supports only a corner of recording mediums laying above spacer  302  and recording medium support  314 , by filling the opening of the corner of the top surface. Thus, as stacker lift  306  moves in a downward direction, recording medium support  314  moves downward at a faster rate than the top surface of spacer  302  thus accommodating the additional thickness introduced by stapling multiple recording mediums together. In this way, arms such as arm  326 ,  226  and/or  126  may be used to accommodate non-uniform thicknesses of recording mediums so that a top surface of a stack of recording mediums (or objects) may be maintained at a desired position. 
   While the shape of recording medium support  314  is shown to be substantially rectangular, other geometries may be used as may be appropriate. For example, substantially triangular shape may be used for stapled documents. 
   It would appreciated that various of the above-disclosed and other features and functions or alternatives thereof, may be desirably combined into many other different systems or applications. Also, that various presently unseen 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.