Abstract:
A method of automatically pivoting a pick arm assembly away from a media support in a printer by providing a printhead carriage with a sloped feature and providing a linking assembly coupled to the pick arm assembly with a ramped feature wherein pivoting the pick arm assembly away from the media support occurs when the printhead carriage travels along the carriage scan path.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    Reference is made to commonly assigned, co-pending U.S. patent applications: 
         [0000]    Ser. No. ______ by Wayne E. Stiehler and Sathiyamoorthy T. Sivanandam (Docket 96429) filed of even date herewith entitled “Media Stopper For A Printing System”;
 
Ser. No. ______ by Wayne E. Stiehler and Sathiyamoorthy T. Sivanandam (Docket 96276) filed of even date herewith entitled “Pick Roller Retraction In A Carriage Printer”;
 
Ser. No. ______ by Wayne E. Stiehler and Sathiyamoorthy T. Sivanandam (Docket 96535) filed of even date herewith entitled “Media Stopper Method For A Printing System”; and
 
Ser. No. ______ by Wayne E. Stiehler and Sathiyamoorthy T. Sivanandam (Docket 96540) filed of even date herewith entitled “Media Separator For A Printing System”, the disclosures of which are incorporated herein by reference in their entireties.
 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention generally relates to paper handling in a carriage printer, and more particularly to the retraction of the pick roller assembly so that recording media can be more easily loaded. 
       BACKGROUND OF THE INVENTION 
       [0003]    In a carriage printer, such as an inkjet carriage printer, a printhead is mounted in a carriage that is moved back and forth across the region of printing. To print an image on a sheet of paper or other print medium, the medium is advanced a given nominal distance along a media advance direction and then stopped. While the medium is stopped and supported on a platen, the printhead carriage is moved in a direction that is substantially perpendicular to the media advance direction as marks are controllably made by marking elements on the medium—for example by ejecting drops from an inkjet printhead. After the carriage has printed a swath of the image while traversing the print medium, the medium is advanced, the carriage direction of motion is reversed, and the image is formed swath by swath. 
         [0004]      FIG. 1  shows a schematic side view of a prior art carriage printer having a so-called L-shaped paper path. A variety of rollers are used to advance the medium through the printer. In this example, a pick roller  350  moves the first piece or sheet  371  of a stack  370  of paper (also generically called recording medium herein) at media input support  320  from paper load entry direction  301  toward media retention plate  340 . Media retention plate  340  is disposed along media advance direction  304  and is at an angle α with respect to media input support  320 . Angle a is typically greater than 60 degrees, so that when seen from the side view of  FIG. 1 , media input support  320  and media retention plate  340  look approximately like a letter L. The piece  371  of recording medium is then moved by feed roller  312  and idler roller(s)  323  to advance through the print region  303 , and from there to a discharge roller  324  and star wheel(s)  325 . Carriage  200  moves a printhead die  251  along a carriage scan direction that is into the plane of  FIG. 1  and ink drops  270  are controllably ejected to print an image as the carriage is moved. Supporting the piece  371  of recording medium at print region  303  is a platen  390 . In order to facilitate the printing of borderless prints where the image is printed to the edges of the recording medium, platen  390  can have support ribs  394  in between which is disposed an absorbent medium  392  to catch ink drops that are oversprayed beyond the edges of the recording medium. 
         [0005]    In order to provide sufficient frictional force to advance top piece  371  of recording medium from the stack  370  during the pick operation, pick roller  350  is provided with a high friction surface and is typically biased against the stack  370  with a biasing force. The biasing force can be provided, for example by a spring, or by the weight of the pick roller assembly, or by the motor that drives the rotation of the pick roller. Although the biasing force facilitates the pick operation, the biasing force must be overcome in order to load additional pieces of recording medium at the media input support  320 . If the recording medium is sufficiently stiff, or if there is a sufficient number of sheets of recording medium to provide overall stiffness of the stack being loaded, the recording medium itself can push the pick roller away while the recording medium is being loaded. However, when only a few sheets of low stiffness are being loaded, the biasing force on the pick roller can result in wrinkled or damaged recording medium, which can lead to paper jams in some instances. Since a user may wish to load only a few pieces (or even a single sheet) of low stiffness recording medium, a way of reliable paper loading must be provided for such instances. 
         [0006]    In a paper feeding apparatus described in U.S. Pat. No. 6,547,235 the “draw-out roller” (similar in function to a pick roller) can be moved away from the stack or media or toward the stack of media by using the same motor that is also used to cause the pick roller to rotate. However, that paper feeding apparatus uses two motors and two one-way clutches, requiring additional space and cost. 
         [0007]    What is needed is simple, low cost and compact way of overcoming the pick roller&#39;s biasing force so that even one or two sheets of low stiffness recording medium can be reliably loaded into the printer without causing wrinkling or other damage to the recording medium. 
       SUMMARY OF THE INVENTION 
       [0008]    A preferred embodiment of the present invention includes a method of operating a media feeder in an inkjet printing system. The method comprises providing a media input support, providing a pivotable pick arm assembly including a pick roller that is biased to pivot toward the media input support, providing a rotatable arm including a member that is linked to the pivotable pick arm assembly and a ramped feature, providing a carriage that is movable along a carriage scan direction, the carriage including a holder for an inkjet printhead and a sloped feature that is in line with the ramped feature of the rotatable arm. A next step includes moving the carriage along the carriage scan direction until the sloped feature of the carriage engages the ramped feature of the rotatable arm, thereby rotating the rotatable arm to pull the pivotable pick arm assembly in a direction away from the media input support. The step of rotating the rotatable arm to pull the pivotable pick arm assembly in a direction away from the media input support can include providing a gap between the pick roller and the media input support and loading paper at the media input support after the gap is provided. The method can also include biasing the pick arm assembly to move toward the media input support when the sloped feature of the carriage is not engaged with the ramped feature of the rotatable arm. Further preferred alternatives include providing a media advance motor, providing a feed roller, providing a feed roller gear that is coaxially mounted on the feed roller, providing a pick clutch assembly that includes a first gear disposed proximate the feed roller gear, a second gear engaged with the first gear, and providing a gear train for transmitting power to rotate the pick roller. The method can also include moving the carriage along the carriage scan direction until the sloped feature of the carriage is disengaged from the ramped feature of the rotatable arm, thereby allowing the pivotable pick arm assembly to move in a direction toward the media input support. Further steps can include rotating the media advance motor in a reverse direction to rotate the feed roller and feed roller gear in a reverse direction, engaging the pick clutch assembly with the gear train to provide power to the pick roller, and rotating the pick roller in a direction to advance a piece of media from the media input support toward the feed roller, detecting a lead edge of the piece of media, rotating the media advance motor in a forward direction after the lead edge of the piece of media is detected to have reached the feed roller, and disengaging the pick clutch assembly from the gear train. This last option can be modified to include disengaging the pick clutch assembly from the gear train when the sloped feature of the carriage engages the ramped feature of the rotatable arm. 
         [0009]    Another preferred embodiment of the present invention includes a method of operating a printer including providing a media input support, providing a pivotable pick arm assembly including a pick roller that is biased to pivot toward the media input support, providing a rotatable arm that includes a member that is linked to the pivotable pick arm assembly and a ramped feature. Then, providing a carriage that is movable along a carriage scan direction, the carriage includes an inkjet printhead and a sloped feature that is in line along the carriage scan direction with the ramped feature of the rotatable arm. Further steps include providing a maintenance station proximate the rotatable arm, the maintenance station including a cap and a maintenance station activator arm, providing a media advance motor, providing a feed roller, providing a feed roller gear that is coaxially mounted on the feed roller, providing a pick clutch assembly including a first gear disposed proximate the feed roller gear, and a second gear engaged with the first gear, providing a gear train for transmitting power to rotate the pick roller, and then moving the carriage along the carriage scan direction until the sloped feature of the carriage engages the ramped feature of the rotatable arm, thereby disengaging the pick clutch assembly. Further steps include moving the carriage along the carriage scan direction until the printhead is over the maintenance station and the sloped feature of the carriage engages the maintenance station activator arm, and rotating the media advance motor in reverse to move the cap into a printhead capping position. 
         [0010]    These, and other, aspects and objects of the present invention will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following description, while indicating preferred embodiments of the present invention and numerous specific details thereof, is given by way of illustration and not of limitation. For example, the summary descriptions above are not meant to describe individual separate embodiments whose elements are not interchangeable. In fact, many of the elements described as related to a particular embodiment can be used together with, and possibly interchanged with, elements of other described embodiments. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications. The figures below are intended to be drawn neither to any precise scale with respect to relative size, angular relationship, or relative position nor to any combinational relationship with respect to interchangeability, substitution, or representation of an actual implementation. 
         [0011]    These and other features and advantages of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings wherein there is shown and described an illustrative preferred embodiment of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a schematic side view of a prior art printer having an L-shaped paper path; 
           [0013]      FIG. 2  schematically shows an inkjet printer system; 
           [0014]      FIG. 3  is a perspective view of a printhead; 
           [0015]      FIG. 4  is a perspective view of the printer of the present invention; 
           [0016]      FIG. 5  is a perspective view of a carriage of the printer of the present invention; 
           [0017]      FIG. 6  is a perspective view a printhead mounted onto the carriage of  FIG. 5 ; 
           [0018]      FIG. 7  is a perspective view of an ink tank loaded into the printhead of  FIG. 6 ; 
           [0019]      FIG. 8  a perspective view of the carriage, printhead and ink tanks, rotated with respect to  FIGS. 5-7 ; 
           [0020]      FIG. 9  is a side perspective view of a portion of an inkjet printing system with the pick arm assembly biased to pivot toward the media input support according to a preferred embodiment of the present invention; 
           [0021]      FIG. 10  is a side perspective view of a portion of the inkjet printing system of  FIG. 9  with the pick arm assembly pivoted away from the media input support according to a preferred embodiment of the present invention; 
           [0022]      FIG. 11  is a close-up side perspective view similar to  FIG. 10  with the pick arm assembly held away from the media input support; 
           [0023]      FIG. 12  is a close-up side perspective view with the pick arm assembly biased against the media input support and the pick clutch assembly rotating toward engagement with the gear train; 
           [0024]      FIG. 13  is a close-up side perspective view with the pick arm assembly biased against the media input support and the pick clutch assembly fully engaged; 
           [0025]      FIG. 14  is a close-up side perspective view with the pick arm assembly biased against the media input support and the pick clutch assembly rotating out of engagement with the gear train; 
           [0026]      FIG. 15  is a side perspective view from an opposite side relative to  FIG. 9 ; 
           [0027]      FIG. 16  is a perspective close-up view of a rotatable arm according to a preferred embodiment of the invention; 
           [0028]      FIG. 17  is a perspective close up view of the rotatable arm, the pivotable pick arm assembly and a link arm that links them; 
           [0029]      FIG. 18  is a close-up side perspective view of a portion of the views of  FIGS. 12 and 13 ; 
           [0030]      FIG. 19  is a side perspective view where the pick roller is moved farther away from the media input support than the gap provided when the ramp feature is engaged; 
           [0031]      FIG. 20  is a close-up side perspective view of rotatable arm, pick clutch assembly, link arm and pivotable pick arm assembly; and 
           [0032]      FIG. 21  is a side perspective view of a portion of an inkjet printing system including a maintenance station, according to a preferred embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0033]    Referring to  FIG. 2 , a schematic representation of an inkjet printer system  10  is shown, for its usefulness with the present invention and is fully described in U.S. Pat. No. 7,350,902 which is incorporated by reference herein in its entirety. Inkjet printer system  10  includes an image data source  12 , which provides data signals that are interpreted by a controller  14  as being commands to eject drops. Controller  14  includes an image processing unit  15  for rendering images for printing, and outputs signals to an electrical pulse source  16  of electrical energy pulses that are inputted to an inkjet printhead  100 , which includes at least one inkjet printhead die  110 . 
         [0034]    In the example shown in  FIG. 2 , there are two nozzle arrays  120  and  130  that are each disposed along a nozzle array direction  254 . Nozzles  121  in the first nozzle array  120  have a larger opening area than nozzles  131  in the second nozzle array  130 . In this example, each of the two nozzle arrays has two staggered rows of nozzles, each row having a nozzle density of 600 per inch. The effective nozzle density then in each array is 1200 per inch (i.e. d= 1/1200 inch in  FIG. 2 ). If pixels on the recording medium  20  were sequentially numbered along the paper advance direction, the nozzles from one row of an array would print the odd numbered pixels, while the nozzles from the other row of the array would print the even numbered pixels. 
         [0035]    In fluid communication with each nozzle array is a corresponding ink delivery pathway. Ink delivery pathway  122  is in fluid communication with the first nozzle array  120 , and ink delivery pathway  132  is in fluid communication with the second nozzle array  130 . Portions of ink delivery pathways  122  and  132  are shown in  FIG. 2  as openings through printhead die substrate  111 . One or more inkjet printhead die  110  will be included in inkjet printhead  100 , but for greater clarity only one inkjet printhead die  110  is shown in  FIG. 2 . The printhead die are arranged on a mounting support member as discussed below relative to  FIG. 3 . In  FIG. 2 , first fluid source  18  supplies ink to first nozzle array  120  via ink delivery pathway  122 , and second fluid source  19  supplies ink to second nozzle array  130  via ink delivery pathway  132 . Although distinct fluid sources  18  and  19  are shown, in some applications it may be beneficial to have a single fluid source supplying ink to both the first nozzle array  120  and the second nozzle array  130  via ink delivery pathways  122  and  132 , respectively. Also, in some embodiments, fewer than two or more than two nozzle arrays can be included on inkjet printhead die  110 . In some embodiments, all nozzles on inkjet printhead die  110  can be the same size, rather than having multiple sized nozzles on inkjet printhead die  110 . 
         [0036]    The drop forming mechanisms associated with the nozzles are not shown in  FIG. 2 . Drop forming mechanisms can be of a variety of types, some of which include a heating element to vaporize a portion of ink and thereby cause ejection of a droplet, or a piezoelectric transducer to constrict the volume of a fluid chamber and thereby cause ejection, or an actuator which is made to move (for example, by heating a bi-layer element) and thereby cause ejection. In any case, electrical pulses from electrical pulse source  16  are sent to the various drop ejectors according to the desired deposition pattern. In the example of  FIG. 2 , droplets  181  ejected from the first nozzle array  120  are larger than droplets  182  ejected from the second nozzle array  130 , due to the larger nozzle opening area. Typically other aspects of the drop forming mechanisms (not shown) associated respectively with nozzle arrays  120  and  130  are also sized differently in order to optimize the drop ejection process for the different sized drops. During operation, droplets of ink are deposited on a recording medium  20  (also sometimes called paper, print medium or medium herein). 
         [0037]      FIG. 3  shows a perspective view of a portion of a printhead  250 , which is an example of an inkjet printhead  100 . Printhead  250  includes two printhead die  251  (similar to inkjet printhead die  110  of  FIG. 2 ) that are affixed to a common mounting support member  255 . Each printhead die  251  contains two nozzle arrays  253 , so that printhead  250  contains four nozzle arrays  253  altogether. The four nozzle arrays  253  in this example can each be connected to separate ink sources. Each of the four nozzle arrays  253  is disposed along nozzle array direction  254 , and the length of each nozzle array along nozzle array direction  254  is typically on the order of 1 inch or less. Typical lengths of recording media are 6 inches for photographic prints (4 inches by 6 inches) or 11 inches for paper (8.5 by 11 inches). Thus, in order to print a full image, a number of swaths are successively printed while moving printhead  250  across the recording medium  20 . Following the printing of a swath, the recording medium  20  is advanced along a media advance direction that is substantially parallel to nozzle array direction  254 . 
         [0038]    Also shown in  FIG. 3  is a flex circuit  257  to which the printhead die  251  are electrically interconnected, for example, by wire bonding or TAB bonding. The interconnections are covered by an encapsulant  256  to protect them. Flex circuit  257  bends around the side of printhead  250  and connects to connector board  258 . When printhead  250  is mounted into the carriage  200  (see  FIG. 5 ), connector board  258  is electrically connected to a connector  244  on the carriage  200 , so that electrical signals can be transmitted to the printhead die  251 . 
         [0039]      FIG. 4  shows a portion of a desktop carriage printer. Some of the parts of the printer have been hidden in the view shown in  FIG. 4  so that other parts can be more clearly seen. Printer chassis  300  includes a horizontal base  302 . Carriage  200  is moved back and forth in carriage scan direction  305 , between the right side  306  and the left side  307  of printer chassis  300 , while drops are ejected from printhead die  251  (not shown in  FIG. 4 ) on printhead  250  that is mounted on carriage  200 . This back and forth motion defines a carriage scan path having a right side terminus and a left side terminus. A carriage motor (not shown) moves carriage  200  along carriage guide rail  382 . 
         [0040]    Printhead  250  is mounted in carriage  200 , and multi-chamber ink supply  262  and single-chamber ink supply  264  are mounted in the printhead  250 . The mounting orientation of printhead  250  is rotated relative to the view in  FIG. 3 , so that the printhead die  251  are located at the bottom side of printhead  250 , the droplets of ink being ejected downward in the view of  FIG. 4 . Multi-chamber ink supply  262 , for example, contains three ink sources: e.g. cyan, magenta, and yellow ink; while single-chamber ink supply  264  contains black ink. Toward the right side  306  of the printer chassis  300 , in the example of  FIG. 4 , is the maintenance station  330 . 
         [0041]    In the L-shaped paper path shown in  FIGS. 1 ,  4  and  9 , the recording medium would be loaded along paper load entry direction  301  nearly vertically at an angle a of 60 degrees or more relative to horizontal base  302  (or relative to media retention plate  340 ) against media input support  320  at the rear  309  of the printer chassis. Media input support  320  includes a first side  321  and a second side  322 . Several rollers are used to advance the recording medium through the printer. A pick roller  350  on pick arm assembly  352  is rotated in rotation direction  351  to move the first piece or sheet  371  of a stack  370  of paper or other recording medium in media input support  320  from paper load entry direction  301  to the media advance direction  304 . The paper is then moved by feed roller  312  (as it is rotated in forward rotation direction  313 ) and idler roller(s)  323  to advance toward the print region  303  (disposed along carriage scan direction  305 ). Because the pick roller  350  contacts a top side of the piece  371  of recording medium and the feed roller  312  contacts the opposite side, the rotation direction  351  of pick roller  350  is opposite the forward rotation direction  313  of feed roller  312  in order to advance piece  371  of recording medium through the printer. Feed roller  312  is driven directly by a paper advance motor (not shown) that is connected by belt or gear engagement, for example at drive gear  314 . After the image is printed at print region  303 , the piece  371  of recording medium is further advanced to a discharge roller  324  and star wheel(s)  325 . 
         [0042]      FIG. 5  is a perspective view of carriage  200 . Carriage  200  includes a holder  202  for an inkjet printhead  250  (see  FIGS. 3 ,  6 - 8 ). Printhead die  251  are exposed through window  204  of carriage  200  when printhead  250  is mounted onto carriage  200  ( FIG. 8 ). Carriage  200  includes one or more bushings  205  to glide along carriage guide rod  382  ( FIG. 4 ) in carriage scan direction  305 . Carriage  200  also includes a connector  244  to mate with connector board  258  of printhead  250  ( FIG. 3 ). 
         [0043]      FIG. 6  is a perspective view of printhead  250  mounted in carriage  200 . Printhead  250  includes compartment  272  for multi-chamber ink supply  262  ( FIGS. 3 and 8 ) and compartment  274  for single chamber ink supply  264 . Ink ports  271  receive ink from the ink supplies  262  and  264  and provide the ink to printhead die  251  of printhead  250 .  FIG. 7  shows a perspective view of multi-chamber ink supply  262  loaded into compartment  272  of printhead  250 . 
         [0044]      FIG. 8  is a bottom perspective view of the underside of carriage  200  together with printhead  250  and ink supplies  262  and  264 . A feature shown in  FIG. 8  that is a preferred embodiment of the present invention is sloped feature  210  that is sloped relative to carriage scan direction  305  and that is in line along carriage scan direction  305  with a corresponding ramped feature  412  (described below with reference to  FIGS. 9 and 11 ), such that when sloped feature  210  is engaged with the ramped feature  412 , the pivotable pick arm assembly  352  (including pick roller  350 ) is pivoted in a direction away from media input support  320  ( FIG. 4 ). 
         [0045]      FIG. 9  is a side perspective view (from right side  306  of  FIG. 4 ) of a portion of an inkjet printing system with the pick arm assembly  352  biased to pivot toward the media input support  320  according to a preferred embodiment of the present invention. Pick arm assembly  352  including pick roller  350 , pick roller support arm  355  and support legs  356 , is biased toward media input support  320  by biasing spring  354  located near but beyond the first side  321  of media input support  321 . Biasing spring  354  is attached to pivotable support leg  356 . The biasing support leg  356  near first side  321  has a number of gears mounted on it for transmitting rotational motion to the pick roller  350 . A second biasing spring  354  is located near but beyond the second side  322  of media input support  321  as shown in  FIG. 15 , so that pick roller  350  is disposed between the two biasing springs  354 . The biasing support leg  356  near second side  322  does not have gears attached to it (see  FIG. 15 ). Pick roller support arm  355  is substantially parallel to carriage scan direction  305  and extends beyond the first side  321  and the second side  322  of media input support  320  in order to provide attachment points for the two biasing springs  354  at support legs  356  without interfering with the passage of recording medium (not shown). In  FIG. 9 , carriage  200  is not at its home position near maintenance station  330 , so the sloped feature  210  (see  FIG. 8 ) is not engaged with the ramped feature  412  located near maintenance station  330 . As a result, biasing springs  354  hold pivotable pick arm assembly  352  so that pick roller  350  is against media input support  320 , or against a top piece  371  of media (not shown) at media input support  320 . This is the desirable position of the pick roller  350  for moving recording medium from media input support  320 . However, if the user attempts to load a few sheets of recording medium having low stiffness while the pick roller  350  is biased against the media input support  320 , the recording medium may become wrinkled or damaged while trying to load it. 
         [0046]    Typically a user will load paper between printing jobs when the carriage  200  is at its home position at the maintenance station  330 .  FIG. 10  is a side perspective view of a portion of the inkjet printing system of  FIG. 9  with the pick arm assembly  352  pivoted away from the media input support  320  according to a preferred embodiment of the present invention. The carriage  200  and the carriage guide rail  382  are hidden in the view of  FIG. 10  so that the ramped feature  412  can be seen more clearly. The ramped feature  412 , having been engaged by the sloped feature  210  on the carriage  200  as the carriage approaches the home position overcomes the biasing force of the biasing springs  354  and pivots the pivot arm assembly  352 , including pick roller  350 , away from media input support  320 , as is described in further detail below. The amount of gap provided between the pick roller  350  and the media input support does not need to be large. It has been found that a gap of more than 2 mm (and up to 6 mm or more) is achievable in this manner. A 6 mm gap can accommodate approximately 60 sheets of media having a thickness of about 100 microns (i.e. about 0.004 inch). Even if the sheets individually have low stiffness, a stack of sheets has sufficient combined stiffness not to become wrinkled or damaged.  FIG. 11  is a close-up side perspective view similar to  FIG. 10  with the pick arm assembly  352  held away from the media input support  320 . In  FIG. 11 , both the carriage and the maintenance station are hidden in order to more clearly show further details, including platen  390  (along print region  303 ), support ribs  394 , pick clutch assembly  420 , and gear train  430 . In this close-up view it is also easier to see the gap between pick roller  350  and media input support  320  when the carriage is in the home position to pivot the pick arm assembly  352  away from media input support  320 . Ramped feature  412  is a part of a rotatable arm  410  that is described in more detail below with reference to  FIGS. 16-18 . (By a “rotatable” arm herein is meant an arm that can rotate or pivot in an arc about an axis, and does not imply that the arm can rotate in a full circle.) Rotatable arm  410  is linked to pick arm assembly  352  by link arm  440 . Power to rotate pick roller  350  is controllably provided by the media advance motor that directly drives feed roller  312  via drive gear  314  mounted on one end of the shaft of feed roller  312 . Feed roller gear  311  is coaxially mounted on the opposite end of shaft. Idle gear  316  is always engaged with feed roller gear  311  and with first gear  422  of pick clutch assembly  420 . In other words, first gear  422  of pick clutch assembly  420  is located proximate feed roller gear  311 , but it is only indirectly engaged with feed roller gear  311  in this preferred embodiment through idle gear  316 . Second gear  424  of pick clutch assembly  420  is engaged with first gear  422  and is selectively engageable with engaging gear  432  of gear train  430  (which includes the gears within the dashed line oval in  FIG. 11 ). As described in more detail below, when the sloped feature  210  ( FIG. 8 ) engages ramped feature  412 , not only is pick arm assembly  352  pivoted about pivot point  436  on support leg  356 , but also second gear  424  of pick clutch assembly  424  is held away from engaging gear  432  of gear train  430 , so that no power is transferred to gear train  430 . In particular, pick roller gear  434  is not rotated, so no rotational power is provided to pick roller  350 . 
         [0047]      FIGS. 12 and 13  are a sequence showing how the second gear  424  of pick clutch assembly  420  becomes engaged with engaging gear  432  of gear train  430  in order to provide rotational power to the pick roller. In both  FIGS. 12 and 13  the carriage (not shown) has been moved out of the home position so that ramped feature  412  is no longer engaged by the sloped feature on the underside of the carriage, so that pick arm assembly  352  is biased against the media input support. In  FIG. 12  drive gear  314  is being driven in the reverse direction  317 , causing both feed roller  312  and feed roller gear  311  also to be driven in the reverse direction (indicated by the arrow on the face of feed roller gear  311 ). The rotation of feed roller gear  311  in reverse direction cause the idler gear  316  and first gear  422  of pick clutch assembly  420  also to rotate, which causes pick clutch assembly  420  to rotate downward such that second gear  424  of pick clutch assembly  420  approaches engaging gear  432  of gear train  430 . In  FIG. 12 , the second gear  424  of pick clutch assembly  420  is nearly engaged with engaging gear  432  but not quite, so no power is being transmitted to gear train  430 . In  FIG. 13 , after continued reverse rotation of drive gear  314 , feed roller  312  and feed roller gear  311 , pick clutch assembly  420  has rotated into full engagement so that second gear  424  is engaged with engaging gear  432  of gear train  430 . As a result, rotational power is transmitted through gear train  430  causing pick roller gear  434  and pick roller  350  to rotate in rotation direction  351  to move a piece of media (not shown) toward feed roller  312 . Note that the direction of arrows  351  for rotation of the pick roller  350  and reverse direction  317  for the feed roller  312  are the same. However, because the pick roller  350  is in contact with the top side of the piece of media, and feed roller  312  is in contact with the bottom side of the piece of media, when the piece of media arrives at feed roller  312 , the reversely rotating feed roller  312  tends to push the leading edge of the piece of media backwards. In this way any skew of the leading edge is substantially eliminated. 
         [0048]    After the deskewing of the leading edge is completed, the media advance motor is driven in the forward direction to rotate drive gear  314 , feed roller  312  and feed roller gear  311  in the forward direction  313 . Forwardly rotating feed roller gear  311  causes idle gear  316  and first gear  422  of pick clutch assembly  420  to rotate such that second gear  424  of pick clutch assembly  420  is rotated out of engagement with engaging gear  432  of gear train  430 , as shown in  FIG. 14 . As a result, no rotational power is transmitted through gear train  430 , so no rotational power is provided to pick roller  350 . 
         [0049]      FIG. 15  is a side perspective view (from left side  307  of  FIG. 4 ) of a portion of an inkjet printing system with the pick arm assembly  352  biased to pivot toward the media input support  320  as in  FIG. 9 . The second biasing spring  354  attached to support leg  356  located near second side  322  of media input support  320  can be seen in this view. In addition, a second pivot point  436  on support leg  356  near second side  322  is shown in this view. Unlike the pivot point  436  near first side  321  seen in  FIG. 11  that also serves as an axle for one of the gears of gear train  430 , the pivot point  436  seen in  FIG. 15  has no associated gears. The media advance motor that powers drive gear  314  is hidden in  FIG. 15 , but the motor mount region  318  is indicated. The carriage is also hidden in this view. 
         [0050]      FIG. 16  is a perspective close-up view of rotatable arm  410  in isolation, as viewed approximately from the orientation of  FIG. 15 . When ramped feature  412  (located near first end  416 ) is engaged by sloped feature  210  on the underside of carriage  200  (see  FIG. 8 ), rotatable arm  410  is rotated about hub  415  in rotation direction  413 , causing linking hook member  414  to move substantially in direction  409 . Linking hook member  414  attaches onto coupling pin  442  of link arm  440 , as seen in  FIG. 17 , so that motion in direction  409  causes link arm  440  to pull on lug  358  on support leg  356 , thereby causing support leg  356  of pivotable pick arm assembly  352  to pivot about pivot point  436 . Coupling pin  442  is substantially parallel to carriage scan direction  305 . Link arm  440  also includes a slot  444 . When support leg  356  is being pivoted forward as in  FIG. 17  (providing a gap between pick roller  350  and media input support  320  as in  FIG. 11 ) the lug  358  is typically located at the end of the slot  444 . A spring attachment member  418  located near second end  417  of rotatable arm  410  (opposite first end  416 ) is for attaching an extension spring  360  (see  FIG. 18 ) to bias rotatable arm  410  against rotating in rotation direction  413 . Thus, when the ramped feature  412  is engaged by sloped feature  210  on the underside of carriage, it needs to pull against both biasing springs  354  as well as extension spring  360 . 
         [0051]      FIG. 18  is a close-up side perspective view of a portion of the views of  FIGS. 12 and 13  with some features hidden in order to show other features. Extension spring  360  is shown as being detached from spring attachment member  418 , but in a fully assembled printer it would be attached. Extension spring  360  is configured to pull rotatable arm  410  toward a predetermined position that is defined by bottom edge  419  being in contact with fixed stop  408 . When sloped feature  210  of carriage  200  (see  FIG. 8 ) is engaged with ramped feature  412  of rotatable arm  410 , rotatable arm  410  is rotated away from this predetermined position. 
         [0052]    As described above relative to  FIG. 10 , when carriage  200  is in the home position and ramped feature  412  is engaged, pivotable pick arm assembly  352  is pivoted forward to provide a gap of 2 mm up to 6 mm or more between pick roller  350  and media input support  320 . However, in many cases a user will want to load a stack of media that has a thickness of greater than the gap provided when the ramp feature  412  is engaged. Slot  444  of link arm  440  allows pivotable pick arm assembly  352  to pivot farther forward so that the pick roller  350  is moved away from media input support  320  by more than one centimeter without causing link arm  440  to push on rotatable arm  410 . The side perspective view of  FIG. 19  shows lug  358  of support leg  356  having moved along slot  444  in order to allow pick roller  350  to be moved farther away from media input support  320  than the gap provided when ramp feature  412  is engaged.  FIGS. 17 and 19  also show that idle gear  316  is mounted at hub  415  of rotatable arm  410 . 
         [0053]      FIG. 20  is a close-up side perspective view of rotatable arm  410 , pick clutch assembly  420 , link arm  440  and pivotable pick arm assembly  352  in a configuration such that ramped feature  412  is engaged with sloped feature  210  of carriage  200  (see  FIG. 8 ), and lug  358  is at the rear of slot  444 . In this configuration a top edge  411  (see also  FIG. 16 ) of rotatable arm  410  pulls on finger  426  of pick clutch assembly  420  so that second gear  424  is pulled out of engagement with engaging gear  432  of gear train  430 . As a result, pick roller  350  is not rotated whether the feed roller  312  is rotated in the forward direction  313  or the reverse direction  317  (see  FIGS. 13 and 14 ). 
         [0054]      FIG. 21  is a perspective view of the right side  306  of printer chassis  300 . Maintenance station  330  is similar to the maintenance station described in US Patent Application Publication 2009/0174748, which is incorporated by reference herein in its entirety. Activator arm  338  is analogous to the latching clutch arm of &#39; 748  and has a ramped surface similar to ramped feature  412 . In particular, in the present invention when carriage  200  moves all the way to its home position at maintenance station  330 , sloped feature  210  on the underside of carriage  200  (see  FIG. 8 ), not only engages ramped feature  412 , but also activator arm  338 . When activator arm  338  is engaged, power from the media advance motor is transmitted from feed roller gear  311  to a set of maintenance station gears (only one of which  339  is shown). As described relative to  FIG. 20 , when ramped feature  412  is engaged with sloped feature  210 , no power is transmitted to pick roller  350 , so there is no additional load on the media advance motor when it is powering the maintenance station  330 . When the activator arm  338  is engaged and the media advance motor is rotated in a reverse direction to rotate the feed roller gear  311  in a reverse direction  317  (see  FIG. 13 ), the wiper  332  is moved along direction  333  to wipe the printhead that is positioned over the maintenance station  330 . Further reverse rotation of feed roller gear  311  causes cap  334  to move into a printhead capping position to prepare the printer for a period of nonprinting. Pump  336  can optionally be operated by further reverse rotation. When it is time to begin another print job, the media advance motor is rotated in a forward direction to rotate feed roller gear  311  in a forward direction  313  (see  FIG. 14 ) and the cap  334  is moved out of the printhead capping position. Continued forward rotation of the media advance motor then causes wiper  332  to move in a direction that is opposite direction  333  in order to wipe the printhead. Pump  336  can optionally be operated by further forward rotation. 
         [0055]    In  FIG. 21  the housing of pick roller assembly  352  has been hidden in order to show pick roller drive shaft  353  and how it connects pick roller  350  with pick roller drive gear  432 . Also, as seen in  FIG. 21 , both the ramped feature  412  of rotatable arm  410  and the activator arm  338  are located near maintenance station  330  so that they can both be engaged when the carriage  200  enters its home position at the maintenance station. Furthermore, in this preferred embodiment, activator arm  338  is between rotatable arm  410  and maintenance station  330 . 
         [0056]    Having described the features of the apparatus it is now possible to describe the method of operation. Controller  14  (see  FIG. 2 ) of the printer is programmed to operate the various functions of the printer, including the functions of the motor that moves the carriage, and the motor that advances the media. When the carriage  200  is out of its home position at the maintenance station  330  so that sloped feature  210  is not engaged with ramped feature  412  of rotatable arm  410 , the pick arm assembly  352  is biased toward the media input support  321 . When the carriage  200  is moved to a position such that sloped feature  210  engages with ramped feature  412 , rotatable arm  410  pulls the pivotable pick arm assembly  352  in a direction away from the media input support  320 , thereby providing a gap between pick roller  350  and media input support  320 . In addition, when the ramped feature  412  is engaged, it causes the pick clutch assembly  420  to disengage from gear train  430 , so that no rotational power is provided to the pick roller  350 . At this point paper or other recording media can be easily loaded without wrinkling or other damage. When the carriage  200  is moved along carriage scan direction  305  until the sloped feature  210  is disengaged from ramp feature  412 , the biasing force on the pivotable pick arm assembly  352  causes it to move in a direction toward the media input support  320 . 
         [0057]    While the carriage  200  is out of its home position so that the ramped feature  412  is disengaged, paper or other recording media can be moved out of the media input support  320  by rotating the media advance motor in a reverse direction  317  to rotate the feed roller and feed roller gear in a reverse direction. This causes pick clutch assembly  420  to engage with gear train  430  to provide power to the pick roller and rotate it in a rotation direction  351  to advance a piece of media from the media input support  320  toward the feed roller  312 . A lead edge of the paper can be detected by a mechanical flag, an optical sensor, or other such sensor (not shown). A suitable amount of time is provided for the feed roller  312  to rotate in the reverse direction  317  to oppose the passage of the lead edge in order to straighten out the paper if it is skewed. Then the controller  14  instructs the media advance motor to rotate in the forward direction. This moves the piece of paper toward the print region  303  so that an image can be printed on it. The motion in the forward direction  313  of the feed roller causes the pick clutch assembly  420  to disengage from gear train  430  so that rotational power is no longer provided to pick roller  350 . Thus the pick roller  350  does not tend to move the next piece of paper out of media input support  320  until the controller  14  later instructs the media advance motor to rotate in reverse again, after the previous page is discharged from the printer. 
         [0058]    When the carriage moves into its home position for maintenance operations, not only does the engaged ramped feature  412  cause the pick arm assembly  352  to move away from media input support  320  and stop transmission of rotational power to the pick roller  350 , in addition the engagement of the activator arm  338  enables transmission of power from the media advance motor through the feed roller gear  311  to power the various maintenance station operations such as wiping, capping, and pumping. In some printers the wiper blades are substantially perpendicular to the carriage scan direction  305  and are positioned at the end of travel of the carriage, so that the nozzle face is wiped in a direction from nozzle array  251  to nozzle array  253 . This can cause cross-contamination of the nozzle arrays  253  due to the different inks in the different nozzle arrays. In the preferred embodiment shown in  FIG. 21 , the wiper  332  is substantially parallel to carriage scan direction  305 . In order for wiper  332  to wipe the printhead face, the wiper must be mechanically moved past the printhead along direction  333 , which is substantially parallel to nozzle array direction  254  (see  FIG. 3 ). Wiping along the nozzle array direction  254  is significantly less prone to cross-contamination of nozzle arrays  253 . After the carriage  200  is moved into maintenance station  330  and activator arm  338  is engaged, the controller  14  instructs the media advance motor to rotate in reverse direction. This first causes wiper  332  to move along direction  333  to wipe the printhead face. Further reverse rotation causes the cap  334  to move into a printhead capping position so that volatile components are less likely to evaporate from the ink at the printhead nozzle face. Further reverse rotation can cause the pump  336  to apply suction to the cap in order to withdraw some ink from the nozzles for cleaning or priming. 
         [0059]    When it is time for the next printing job, the controller  14  instructs the media advance motor to rotate in a forward direction. This moves the cap  334  out of its capping position. Further forward rotation of the media advance motor causes the wiper to wipe the printhead nozzle face by moving in a direction opposite to direction  333 . Further forward rotation can cause the pump  336  to apply suction to the cap to remove waste ink from the cap. The controller  14  then instructs the carriage to move out of the maintenance station  330  so that power is disengaged from the maintenance station. The biasing force on the pivotable pick arm assembly  352  pulls the pick roller  350  into contact with top piece of media in the media input support  320 . The controller  14  instructs the media advance motor to rotate in reverse so that power is transmitted to the pick roller  350  and a piece of paper is moved forward for the next print job. 
         [0060]    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. 
         [0061]    PARTS LIST
     10  Inkjet printer system     12  Image data source     14  Controller     15  Image processing unit     16  Electrical pulse source     18  First fluid source     19  Second fluid source     20  Recording medium     100  Inkjet printhead     110  Inkjet printhead die     111  Substrate     120  First nozzle array     121  Nozzle(s)     122  Ink delivery pathway (for first nozzle array)     130  Second nozzle array     131  Nozzle(s)     132  Ink delivery pathway (for second nozzle array)     181  Droplet(s) (ejected from first nozzle array)     182  Droplet(s) (ejected from second nozzle array)     200  Carriage     202  Holder     204  Window     205  Bushing     210  Sloped feature     244  Connector     250  Printhead     251  Printhead die     253  Nozzle array     254  Nozzle array direction     255  Mounting support member     256  Encapsulant     257  Flex circuit     258  Connector board     262  Multi-chamber ink supply     264  Single-chamber ink supply     270  Ink drops     271  Ink port     272  Compartment     274  Compartment     300  Printer chassis     301  Paper load entry direction     302  Base     303  Print region     304  Media advance direction     305  Carriage scan direction     306  Right side of printer chassis     307  Left side of printer chassis     309  Rear of printer chassis     311  Feed roller gear     312  Feed roller     313  Forward rotation direction (of feed roller)     314  Drive gear     316  Idle gear     317  Reverse rotation direction (of feed roller)     318  Motor mount region     320  Media input support     321  First side     322  Second side     323  Idler roller     324  Discharge roller     325  Star wheel(s)     330  Maintenance station     332  Wiper     333  Direction     334  Cap     336  Pump     338  Activator arm (for maintenance station)     339  Maintenance station gear     340  Media retention plate     350  Pick roller     351  Rotation direction     352  Pick arm assembly     353  Pick roller drive shaft     354  Biasing spring     355  Support arm     356  Support leg     358  Lug     360  Extension spring     370  Stack of media     371  First piece of medium     382  Carriage guide rail     390  Platen     392  Absorbent material     394  Support ribs     408  Fixed stop     409  Direction     410  Rotatable arm     411  Top edge     412  Ramped feature     413  Rotation direction     414  Linking hook member     415  Hub     416  First end     417  Second end     418  Spring attachment member     419  Bottom edge     420  Pick clutch assembly     422  First gear (of pick clutch assembly)     424  Second gear (of pick clutch assembly)     426  Finger     430  Gear train     432  Engaging gear (of gear train)     434  Pick roller drive gear     436  Pivot point     440  Link arm     442  Coupling pin