Abstract:
A printer having a sheet tray, a drive for advancing sheets past a marking mechanism, and a picker to remove sheets from an aligned tray includes a load position and a pick position. The trays are selectively moved between the load and pick positions. A transmission is engagable to connect the drive to the tray moving mechanism, whereby the tray is moved between the pick position and the load position by the media sheet advancing drive. The transmission is disengagable to enable advancement of the media sheets without movement of the tray. Starting with both trays in their load positions, one of the trays is moved to its pick position whereat a sheet can be picked; moving the other of the trays to its pick position whereat a sheet of media from each of the trays can be picked; and moving the tray remaining at its pick position from its pick position to its media load position.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to home and office printers, and more specifically to improvements in image receiver media trays and the interface between such trays and the printer. 
       BACKGROUND OF THE INVENTION 
       [0002]    Home and office printers that have trays into which image receiver material sheets can be loaded and fed to a print station are well known. Such trays are usually adapted to receive several standard-sized sheets of image receiver media, such as letter (8.5″×11″ or 215.9×279.4 mm), A4 (210.0×297.0 mm), and legal (8.5″×14″ or 215.9×355.6 mm). 
         [0003]    Often, the printers are capable of producing photo-quality prints on smaller sheets of image receiver media, such as 4″×6″ (101.6×152.4 mm) that require no more than one-half of the width of the media path through the printer. Of course these smaller sheets of image receiver media do not necessarily need to be of photo-quality material, and can be card stock, labels, or even plain paper. For convenience, the phrases “auxiliary media” and “auxiliary tray” will be used to designate any image receiver media that require no more than one-half of the width of the media path through the printer and any tray that is adapted to receive such photo media, respectively. Commercially available auxiliary trays have only a single tray and are manual in the sense that the user, after loading the tray with auxiliary media, must physically push the auxiliary tray into a position which allows the media to be picked. 
         [0004]    Since auxiliary media sheets require no more than one-half of the width of the media path through the printer, it would be convenient to provide side by side stacks of such media sheets so that two sheets, one from one stack and the other from the other stack, can be picked simultaneously and fed through the printer at the same time. This would provide higher throughput, since two sheets can be printed simultaneously. By printing on two sheets side by side, the number of times per sheet that the carriage must be turned around to print a new swath is cut in half. This reduction in turnaround times is one factor leading to higher throughput. Another factor is the faster paper loading and ejecting of two sheets at a time. Further, it would provide additional flexibility if only a single sheet could be picked and fed through the printer so that an odd number of sheets could be printed without the requirement of feeding an extra, blank sheet through the printer. 
       SUMMARY OF THE INVENTION 
       [0005]    According to a feature of the present invention, a printer having a tray for receiver media sheets, a sheet drive for advancing media sheets past a marking mechanism, and a picker to remove media sheets from an aligned tray includes a media load position at which the tray is accessible for inserting a supply of media sheets and a media pick position at which the tray is aligned with the picker. A tray moving mechanism selectively moves the tray between the media load and pick positions. A transmission is engagable to connect the drive of the sheet feeding mechanism to the tray moving mechanism, whereby the tray is moved between the pick position and the media load position by the media sheet advancing drive. The transmission is disengagable to enable advancement of the media sheets without movement of the tray. 
         [0006]    According to another feature of the present invention, the printer includes first and second trays. The printer has a media load position and a media pick position for each of the trays. The trays are aligned side by side when both are at their pick positions, such that the picker can simultaneously remove a sheet from each tray. 
         [0007]    In a preferred embodiment, the mechanism for moving each tray is connectable independently to each tray so as to move one tray at a time from its media load position to its pick position such that the picker: can remove a sheet from the first tray at the pick position before the second tray reaches the pick position, and can remove a sheet from the tray remaining at the pick position after the other tray has been moved from the pick position. 
         [0008]    According to yet another feature of the present invention, a method of producing a single print using a printer that has two media trays, a media load position for each tray, and a pick position for each tray includes the steps of starting with both trays in their media load positions, moving one of the trays to its pick position; picking a sheet of media from the one tray; moving the other of the trays to its pick position; and moving both trays from their pick positions to their media load positions without picking additional sheets of media. 
         [0009]    According to still another feature of the present invention, a method of producing an even number of prints includes the steps of starting with both trays in their media load positions, moving one of the trays to its pick position; moving the other of the trays to its pick position; picking a sheet of media from each of the trays; and moving both trays from their pick positions to their media load positions without picking additional sheets of media. 
         [0010]    According to yet another feature of the present invention, a method of producing an odd number of prints includes the steps of starting with both trays in their media load positions, moving one of the trays to its pick position; moving the other of the trays to its pick position; picking a sheet of media from each of the trays; moving one of the trays to its media load position; picking a sheet of media from the tray remaining at its pick position; and moving the tray remaining at its pick position from its pick position to its media load position. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a front perspective view of a portion of a printer and media trays according to the present invention; 
           [0012]      FIG. 2  is a top plan view of the auxiliary media tray of  FIG. 1 ; 
           [0013]      FIG. 3  is a front view of the printer and media trays of  FIG. 1 ; 
           [0014]      FIG. 4  is a side view of the printer and media trays of  FIG. 1 ; 
           [0015]      FIG. 5  is a side elevation view of a portion of the printer of  FIG. 1  showing details of the media sheet feeding mechanism; 
           [0016]      FIG. 6  is a side elevation view similar to  FIG. 5  with parts removed for a clearer view of details otherwise hidden; 
           [0017]      FIG. 7  is a side elevation view similar to  FIG. 5  with parts removed for a clearer view of details otherwise hidden; 
           [0018]      FIGS. 8-10  are views of a rocker gear transmission in various states; 
           [0019]      FIG. 11  is a view of the rocker gear transmission and a leaf spring; 
           [0020]      FIGS. 12 and 13  show different states of a leaf spring engagement mechanism; and 
           [0021]      FIGS. 14-25  show a dual tray in various states of operation. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0022]      FIG. 1  is a front perspective view of a portion of a printer  10  and image receiver main tray  12  and an auxiliary tray  14  according to a preferred embodiment of the present invention. The printer housing has been removed for a clearer rendering of the interior of the printer. Main media tray  12  is adapted to receive media sheets of standard sizes, such as letter (8.5″×11″ or 215.9×279.4 mm), A4 (210.0×297.0 mm), and legal (8.5″×14″ or 215.9×355.6 mm). A slot is provided in the printer for insertion of media auxiliary tray  14 . The auxiliary tray is located through holes in the left and right lateral sidewalls  16  and  18 , respectively, and it rests on the top of main tray  12 . 
         [0023]    As illustrated in  FIG. 2 , auxiliary tray  14  holds two side by side stacks  20  and  22  of media, such as for example 4″×6″ photo media. The two media stacks are loaded in left and right sub-trays  24  and  26 , respectively. As used herein, the terms “left” and “right” and “top” and “bottom” are intended to designate elements as viewed in the drawings, and are not indicative of any specific intended orientation of printer  10  during use. 
         [0024]      FIGS. 3 and 4  are front and side views of printer  10  and illustrate main tray  12  and auxiliary tray  14 . A carriage  28  carries a print head and a plurality of ink cartridges back and forth across the media path to produce images as is well known in the field. 
         [0025]    Media sheets, whether from main tray  12  or auxiliary tray  14 , are “picked” by the printer. The illustrated embodiment includes a turn roller type pick system, but a person skilled in the art would understand that there are many known pick systems, such as a pick arm type system, that could be employed with only minor modification to the printer and trays. The media sheets move from a tray or trays to a turn roller  30 , to a feed roller  32 , and finally to an output roller  34 . Referring to  FIG. 5 , a linefeed motor  36  and a timing belt  38  power the movement of output roller  34 , feed roller  32  and turn roller  30 . When the media sheets within auxiliary tray  14  are directly below turn roller  30 , lift plates on the auxiliary tray are raised to push the media sheets in the tray upwards until the top most sheet presses against the turn roller. The turn roller rotation will then transport that media sheet from the auxiliary tray to feed roller  32 . A lift plate in the main tray pushing up against the auxiliary tray lift plates raises the lift plates of the auxiliary tray. The main tray lift plate is in turn pushed up by means of a conventional cam mechanism (not shown) in the printer. If there is paper in the main tray, the paper will transfer the force from the main tray lift plates to the auxiliary lift plates. Optionally, the back of the auxiliary lift plates each have a leaf spring (not shown) attached, so that if the two auxiliary trays contain different amounts of media, the leaf springs will accommodate the different stack heights and push the media to the proper height for pick up. 
         [0026]    In order for media to be fed from auxiliary tray  14  to turn roller  30 , the auxiliary tray must move horizontally towards the turn roller, in the direction of arrow  40  of  FIG. 6 , until the media is directly below the turn roller. Auxiliary tray  14  (shown in  FIG. 4 ) derives its motion from linefeed motor  36  through a rack  42  and a rocker gear transmission  44 , and does not require a separate motor. As such this system is a low cost method that achieves the advantages of the automatic tray. Rocker gear transmission  44  selectively attaches rack  42  to output roller  34 . When rocker gear transmission  44  is engaged, as explained below, the rotation of the output roller will drive the photo tray motion due to a nominal gripping friction force between rocker arm  46  and the output roller. Referring to  FIG. 7 , the rocker gear transmission includes a rocker arm  46  that is free to rotate co-axially with output roller  34 . There are three states for the rocker arm  46 . A “forwards” state is illustrated in  FIG. 8  wherein the auxiliary tray is moved inwardly of the printer to the pick position via an output roller gear  48 , a transmission gear  50 , an idler gear  52 , a gear  54  that is fixed to a gear shaft  56 , and rack  42  of  FIG. 6 . Rocker arm  46  has a “backwards” state is illustrated in  FIG. 9  wherein the auxiliary tray is moved outwardly of the printer to a media load position via output roller gear  48 , a transmission gear  58 , idler gear  52 , gear  54  fixed to a gear shaft  56 , and rack  42  (shown in  FIG. 6 ). Finally, rocker gear transmission  44  has a “disengaged” state as illustrated in  FIG. 10 , wherein line feed motor  36  may move media for printing while the auxiliary tray remains stationary. 
         [0027]    As illustrated in  FIG. 11 , rocker arm  46  is normally held in its disengaged,  FIG. 10  state by a pin  60  on the rocker arm. The pin aligns with a hole through a leaf spring  62  to prevent rotation of the rocker arm with output roller  34 . In this neutral state of rocker gear transmission  44 , there is no transmission of power from linefeed motor  36  to the auxiliary tray  14 . 
         [0028]    As set forth above, pin  60  on rocker arm  46  must disengage from the hole in leaf spring  62  before rocker gear transmission can effect movement of either sub tray  24  or  26  of auxiliary tray  14 . Movement of the leaf spring effects such disengagement so that pin  60  is no longer captured in the hole of the leaf spring. During printing, carriage  28  moves left and right (as viewed in  FIG. 12 ) across the media. However, when a sub tray is to be moved, carriage  28  travels to an extreme left position, “stand-by” position illustrated in  FIG. 13 , whereby the carriage bumps against leaf spring  62 , causing the leaf spring to deflect to the left. This deflection frees pin  60  from the leaf spring and allows the rocker arm  46  to move from its disengaged state. Pin  60  continues to keep the leaf spring  62  in deflection until the pin is returned to the hole, as described below. The carriage is free to move off once it frees the rocker from the leaf spring, allowing the carriage to perform other functions if appropriate. Thus the leaf spring serves as an engagement/disengagement mechanism for the rocker gear transmission. 
         [0029]    Referring to  FIG. 14 , auxiliary tray  14  includes a fixed tray support  64 , left &amp; right movable sub trays  24  and  26 , respectively, rocker gear transmission  44 , leaf spring  62  for carriage activation, gear shaft  56  from rocker gear transmission  44 , a pinion gear engaging rack  42 , and left and right tray biasing springs  68  and  70 , respectively. Gear shaft  56  is connected to gear  54  of rocker gear transmission  44  of  FIG. 8 . Gear shaft  56  rotates as one with pinion gear  66 . In turn, rotation of pinion gear  66  translates to linear motion of sub trays  24  and  26  via racks  42  and  43  on the trays as illustrated in  FIG. 15 . Although the illustrated embodiment provides all of these elements as part of the assembly of auxiliary tray  14 , a person skilled in the art would understand that many of the elements could be incorporated into the printer housing and not be removable with the auxiliary tray. In this manner, several lower priced trays, or simpler trays could be used. 
         [0030]    Sub-trays  24  and  26  can move independently of each other, allowing media from either one or both stacks to be “picked” by the printer. In  FIG. 15 , both of the sub trays are removed from their pick positions, allowing media to be fed from main tray  12  and allowing an operator to load media into the sub trays. Pinion gear  66  is engaged with rack  43 . However, rack  42  is slightly shorter than sub tray  24  and is not engaged with pinion gear  66 . As the pinion gear rotates, right sub tray  26  moves to its pick position illustrated in  FIG. 16 . 
         [0031]    Referring to  FIG. 17 , as right sub tray  26 , traveling in the direction of arrow  72  nears its pick position, an overlap tab feature  74  on the right sub tray engages a corresponding overlap tab feature  76  on left sub tray  24 , pushing the left sub tray a few millimeters to engage rack  42  with pinion gear  66  as shown in  FIG. 18 . 
         [0032]    At this position, rack  43  of right sub tray  26  starts to disengage from pinion gear  66 . A biasing spring  78  pushes right sub tray  26  an additional few millimeters beyond the end of the rack as sequentially illustrated in  FIGS. 19A and 19B  until the right sub tray reaches its final pick position shown in  FIG. 20 . At this stage, the printer may move rocker arm  46  to its  FIG. 10  position to disengage transmission  44  by rotating the output roller gear  48  in the opposite direction a distance equal to or greater than the distance required to reseat pin  60  on the rocker arm  46  into the hole on the leaf spring  62 . Then the printer picks a media sheet from right sub tray  26 , and produces one print. If rocker arm transmission  44  is left engaged, left sub tray  24  continues to move, now driven by pinion gear  66  until the left sub tray also reaches its pick position as illustrated in  FIG. 21 . Now, both trays are positioned ready to have the media therein picked for an even number of prints. 
         [0033]      FIG. 22  illustrates the initial step of returning the sub trays to their media load positions. As left sub tray  24  moves in the direction of arrow  80  due to the reversal of pinion gear  66 , its overlap tab feature  76  contacts overlap tab feature  74  of right sub tray  26  so that the right sub tray moves far enough to reengage its rack  43  with pinion gear  66 . As left sub tray  24  reaches the end of engagement between its rack  43  and pinion gear  66 ,  FIG. 23 , the printer is ready to print the final page of an odd number multiple page print job. A biasing feature  82  pushes the tray a few more millimeters to fully disengage that rack and the pinion gear,  FIG. 24 . Right sub tray  26  continues to be driven by the pinion gear. 
         [0034]    Right sub tray  26  continues to move back toward its media load position as shown in  FIG. 25 . The printer has finished the print job and is in its home position ready for media loading by end user. The unique advantage of having the trays move independently of each other is that in the event that a user prints an odd number of pages, the left sub tray will retract just before the final page is going to be printed so that only the right tray media will get picked. This prevents the situation whereby a blank piece of media gets picked and pushed through the entire media path. This improves the user&#39;s satisfaction by providing a truly clean and noninterfering method for printing an odd number of sheets. 
         [0035]    The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention. 
       PARTS LIST 
       [0000]    
       
           10 . printer 
           12 . main tray 
           14 . auxiliary tray 
           16 . left side wall 
           18 . right side wall 
           20 . left stack 
           22 . right stack 
           24 . left sub-tray 
           26 . right sub tray 
           28 . carriage 
           30 . turn roller 
           32 . feed roller 
           34 . output roller 
           36 . line feed motor 
           38 . timing belt 
           40 . arrow 
           42 . rack 
           44 . rocker gear transmission 
           46 . rocker arm 
           48 . output roller gear 
           50 . transmission gear 
           52 . idler roller 
           54 . gear 
           56 . gear shaft 
           58 . transmission gear 
           60 . pin 
           62 . leaf spring 
           64 . fixed tray support 
           66 . pinion gear 
           68 . left tray biasing spring 
           70 . right tray biasing spring 
           72 . direction 
           74 . right overlap tab feature 
           76 . left overlap tab feature 
           78 . right biasing spring 
           80 . arrow 
           82 . biasing feature