Abstract:
A shuttle system transfers an ink-jet pen between a carriage and a shuttle access location on a printer front panel. When a pen load button is pushed, the shuttle will move to an access position. In the access position, the shuttle will open a door and come beyond the front face of the printer. This allows the user to drop the pen(s) into place on the shuttle. Then when the button is pushed again, the pen shuttle will transfer the pens back into the printer, with the door closing, and automatically loads the pen(s) into the printer carriage without manual user intervention. The pen shuttle will then move to a rest position for normal printer operation. If the pen load button is pressed again, the pen shuttle moves back to the carriage and unloads the pen(s) automatically. The pen shuttle again opens the access door and presents the pens to the user. The shuttle has pen wipers and capping structures mounted for movement with the shuttle, allowing for pen service functions to be performed without the need for an additional service station.

Description:
TECHNICAL FIELD OF THE INVENTION 
     This invention relates to printers utilizing removable printing structures. 
     BACKGROUND OF THE INVENTION 
     Printers such as ink-jet printers employ printing elements which require periodic removal and replacement. In the case of ink-jet printers, the printing elements include nozzle arrays typically mounted on pens or print cartridges, and can require periodic replacement as the nozzle array wears out, becomes clogged, or when an internal ink supply becomes exhausted. 
     In the past, the user has manually inserted and removed the ink-jet pens or print cartridges into receptacles on the printer, e.g. on a traversing carriage. This in turn requires that the receptacles be readily accessible to the user, typically by lifting a cover to gain access. User access becomes problematic for some printers, and so it would be advantageous to provide a solution to the problem of removing and replacing ink-jet pens, print cartridges or other printing elements in a printer in which the user does not have ready access to the receptacle in which the printing element is mounted during printing operations. 
     SUMMARY OF THE INVENTION 
     In accordance with an aspect of the invention, a printer is described wherein a pen carrier is provided for transporting the pen from a front panel or other location readily accessible to the user, to the printer carriage receptacle which holds the pen during printing operations. The user simply drops the ink jet pens into position on the carrier, and initiates a load sequence. The carrier then takes the pens and loads them into the carriage for printing. This allows simple loading and unloading of ink-jet pens even when the carriage is buried at the back of the machine and the user only has access to the front face of the machine. 
     In accordance with another aspect of the invention, a method for loading ink-jet pens into a traversing carriage of an ink-jet printer is described, and includes the following: 
     loading an ink-jet pen into a pen shuttle positioned at a shuttle access station; 
     with the carriage positioned at a carriage loading station, moving the pen shuttle from the access station to the carriage loading station; 
     transferring the pen from the pen shuttle to a pen stall in the carriage. 
     In accordance with another aspect of the invention, a printer is disclosed, and includes a traversing carriage having a receptacle for holding a printing element during printing operations. A printing element shuttle is arranged for movement along a shuttle path which includes a shuttle access station and a carriage loading station. The printer further has a shuttle drive system for moving the shuttle along the shuttle path, the shuttle and the carriage arranged to transfer a printing element between the carriage and the shuttle with the carriage positioned at the carriage loading station. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     These and other features and advantages of the present invention will become more apparent from the following detailed description of an exemplary embodiment thereof, as illustrated in the accompanying drawings, in which: 
     FIG. 1 is a partially-broken away isometric view of an ink-jet printer embodying aspects of this invention. 
     FIG. 2 is a side cross-sectional view taken along line  2 — 2  of FIG. 1, showing the pen carrier. 
     FIG. 2A is a cross-sectional view taken along line  2 A— 2 A of FIG.  2 . 
     FIG. 2B is a side cross-sectional view showing the capping of a pen at the service area. 
     FIG. 3 is a partial top cross-sectional view, taken along line  3 — 3  of FIG.  2 . 
     FIG. 3A is a cross-sectional view taken along line  3 A— 3 A of FIG.  3 . 
     FIG. 4 is an isolation view illustrative of a shuttle motor drive for the printer of FIG.  1 . 
     FIG. 5 is a partial side cross-sectional view taken along the same line as for FIG. 2, showing the shuttle in a loading/unloading position at the front of the printer, with the front panel door opened. 
     FIG. 5A is a partial side cross-sectional view taken along the same line as for FIG. 2, showing the shuttle being moved from the loading/unloading position. 
     FIG. 5B is a partial side cross-sectional view taken along the same line as for FIG. 2, showing the shuttle being moved away the loading/unloading position, with the front panel door and the shuttle door closed. 
     FIG. 5C is a partial side cross-sectional view taken along the same line as for FIG. 2, showing the shuttle approaching the carriage to transfer a shuttle to the carriage. 
     FIG. 6 is a partial side cross-sectional view taken along the same line as for FIG. 2, but showing the shuttle in position at the rear of the printer with the pen transferred between the shuttle and the printer carriage. 
     FIGS. 7A-7C illustrate top views of the shuttle loaded with two pens approaching and engaging carriage to transfer the pens from the shuttle to the carriage, and withdrawing after the transfer has been made. 
     FIGS. 8A-8C illustrate in top views a pen transfer from the carriage to the shuttle. 
     FIG. 9 is a broken-away partial top view of the printer of FIGS. 1-8, showing the carriage, part of the media path, and the shuttle system. 
     FIG. 10 is a simplified control block diagram of the printer of FIGS.  1 - 9 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 shows an isometric view of a portion of a low profile, stackable inkjet printer  50  embodying aspects of this invention. The printer is particularly adapted for use in a stacked arrangement with other equipment in a cabinet or the like. Thus, other equipment may be stacked over the printer  50 . The printer includes an ink-jet pen carriage  200  (FIG. 9) which carries two ink-jet  30 ,  32  pens during printing operations, disposed at the back of the printer. The carriage is mounted for sliding movement along a slider rod  210 , disposed in a generally parallel orientation relative to the front panel of the printer. Thus, with other equipment stacked adjacent the top surface of the printer  50 , it would not be possible to access the printer carriage to manually install/remove the inkjet pens on/from the carriage. This invention provides a technique to transport the pens from the front of the printer to the back for loading in the carriage, and for unloading the pens from the carriage and transporting them to the front of the printer. 
     While the invention is described with respect to an ink-jet printer, aspects of the invention can be employed with other types of printers and other printing structures or elements. For example, the printing structure or element can include or exclude an internal ink reservoir, and the printing structure or element could be an ink reservoir without a device for applying the ink. 
     The printer  50  includes a housing structure  52  and a front panel  54 . The front panel has a set of front panel control switches  56  on one side of the printer, a print media access area  58 , and a hinged access door  60  on the opposite side from the switches  56 . A pull-out media input tray  55  and a pull-out media output tray  57  are positioned in the center of the front panel. The trays allow the user to access the media trays from the front panel of the machine, without requiring access from the top surface of the machine. 
     FIG. 9 is a top partially broken-away view of the printer with the top cover removed. This illustrates a portion of the media path and a platen surface  220  which supports the print medium at a print zone. The print medium is advanced from an input supply below output tray surface  230 , driven through a 180° change in direction, and positioned on platen surface  220  for printing operations. The printer includes a drive roller system as part of a media advance system to pick a sheet of print medium from the input source, and incrementally advance the sheet through the print zone, after completion of a print swath. The pens are mounted on the carriage for traversal along the slider rod  210  to print each swath. The carriage  200  is positioned in the service station area  302  in FIG.  9 . The carriage is driven along the rod  210  to traverse the print area  302  during printing operations. 
     In accordance with an aspect of the invention, a pen shuttle system  100  is provided for transporting pens between the front panel  54  and a pen load/unload area at the back of the printer. Particularly, the access door  60  provides an access location to a pen shuttle  110 , to allow the user to remove pens from the shuttle and place pens in the shuttle for transport to the carriage at the back of the printer. The pen shuttle is shown, e.g.,in FIGS. 2-9. 
     The pen shuttle system  100  includes a shuttle  110  mounted for movement along rails  102 ,  104 . In this exemplary embodiment, the shuttle is driven by a leadscrew  130  rotated by a motor drive including motor  130 , belt  132  and pulleys  134 ,  136  (FIG.  4 ). A threaded traveller nut structure  112  (FIG. 3A) is fixed to the underside of the shuttle floor  114 , and is threaded onto the leadscrew, so that rotational movements of the leadscrew are converted into linear movements along the leadscrew axis  130 A. Of course, other techniques for driving the shuttle could alternatively be employed, including belt or cable drives, rack and pinion gear drive, and the like. 
     In this exemplary embodiment, the printer  50  has two pens, one a monochrome pen, the other a tricolor pen, which are carried on the traversing carriage  200  during printing operations. The shuttle  110  is adapted to carry two pens  30 ,  32  (FIG. 7A) in this embodiment, corresponding to the number of pens carried by the printer carriage, although for other printers, the shuttle can carry a single pen, or more than two pens, as required for the particular printer. The shuttle has an interior wall  120  which defines two shuttle stall spaces  120 A,  120 B (FIG.  9 ). 
     The shuttle  110  includes a floor structure  114 , and opposed side pen latch arms  116 ,  118 , which are hingedly mounted to the floor structure by hinge joints which extend parallel to the axis  130 A of movement of the shuttle. For example, hinge joint  116 A connects latch arm  116  to the lateral edge of the floor  114 . As a result of the connection of the latch arms to the floor structure, the latch arms can pivot outwardly about the hinge joint connection to the floor from upright positions perpendicular to the floor to positions away from the vertical, as shown in FIG. 8A, to be discussed below. Torsion springs bias the latch arms to the upright position. As shown in FIG. 9, for example, each latch arm  116 ,  118  has formed at a distal end a transverse tab portion  116 C,  118 C. This tab portion acts as a stop surface to bear against the pen body, and hold the pen in position in the shuttle. Moreover, the distal end of each latch arm has formed therein a feature  116 B,  118 B which is engaged to open the latch arms as the shuttle engages the carriage. 
     The shuttle has an interior wall  120  which defines two shuttle stall spaces  120 A,  120 B (FIG.  9 ). 
     The shuttle  110  further includes a shuttle door structure  122  hingedly mounted to the floor structure  114  on a pivot pin  122 C (FIG.  2 ), which extends transversely to the axis  130 A. The door structure  122  includes side arms  122 A,  122 B. The latch arms  116 ,  118  are constrained from rotating about their pivots when the pens are being loaded into the shuttle by the side arms of the door structure, which are pivoted upwardly as shown in FIG. 5 during a front panel loading process. 
     A linkage comprising link arms  140 ,  142  is connected between the pen door  60  and a tension spring  146 , attached to a subfloor structure  150  of the printer frame. When the shuttle  110  moves to the front of the printer, the shuttle comes into contact with the hinged door  60 , causing the door to pivot open as the shuttle moves to the end of its forward travel, as illustrated in FIG.  5 . When the shuttle  110  is moved inside the machine, the spring  148  acts on the linkage to close the pen door  60 . 
     FIG. 5 shows one pen  30  and the shuttle  100  in the front load position. A pen latch  160  is fixed to the printer frame structure  162  above the shuttle front load position, one latch for each pen. As the user inserts the pen into the receptacle in the pen shuttle, the pen latch rides over and engages a datum feature  30 A formed in the top lid  30 B of the pen. The latch  150  holds the pen  30  to the shuttle, preventing the pen from shifting or moving out of the loading position when the shuttle is at the position shown in FIG.  5 . The latch also provides tactile feedback to the user that the pen has been properly placed on the shuttle  110 . The latch has an “L” shape that engages the corresponding datum surface  30 A on the top lid  30 B of the pen. As the shuttle  110  is driven by the leadscrew away from the front loading position, the pen  30  is carried away from the latch  160 , becoming disengaged from the latch. As the shuttle continues its journey toward the carriage, the pen  30  remains held at a tilted orientation relative to the vertical. 
     A pen plate  170 ,  172  (FIG. 9) is provided on the shuttle door  122  for each pen. Each pen plate is spring-loaded to a reference so that when the door  122  is closed, the pen is biased to an angled position offset from the vertical, as shown in FIG.  5 B. In this exemplary embodiment, the tilt angle is 7° from the vertical. 
     FIG. 5A shows exemplary pen plate  170 , biased to an outward reference position by a spring  170 A. The plate  170  is hinged for movement about pivot  170 B. A stop surface structure  170 C provides a reference stop to limit the outward movement of the plate to the reference position. When the pen  30  is transferred from the shuttle  110  to the printer carriage  200 , as shown in FIG. 6, the orientation of the pen relative to the vertical changes from 7° to 0°, and the spring  170 A biasing the pen plate  170  compresses to allow the plate to move inwardly to accommodate the rotation of the pen. 
     FIG. 5A shows the shuttle positioned  110  at the front of its path of travel, with a pen  30  installed on the shuttle  110  and the front panel door  60  and shuttle door  122  partially closed. The shuttle door opens by its own weight in this position. When the shuttle  110  travels inwardly from the front position, the shuttle door  122  is closed by interaction of door side cam surfaces, e.g. surface  122 C, with fixed ramp surfaces  102 A,  104 A defined on the guide rails  102 ,  104 , as illustrated in FIG.  5 B. 
     FIG. 5C shows the pen shuttle  110  moved to its load/unload position relative to the printer carriage  200 , to unload the pen into the carriage. As the shuttle approaches the carriage load position at the rear of the printer, the ends of the door arms are captured within a locking channel  180 A,  182 A defined in respective lock structures  180 ,  182  located along the guide rails  102 ,  104  adjacent the carriage service area, preventing the shuttle door from opening. The locking channels permit movement of the ends of the door arms along the direction of the shuttle axis, but constrains the door arms from rotating upwardly or downwardly. This allows the door to exert force against the pen as the shuttle brings the pen into engagement with the carriage, without allowing the door to open. In an exemplary embodiment, the door exerts about 4 pounds of force on the pen as the pen is transferred into engagement with the carriage, and the locking structures prevent the door  122  from pivoting about its hinge in reaction to this transfer force. 
     The printer carriage  200  is moved away from the service station position  300  (FIG. 9) to provide clearance for the cap sled structure mounted on the shuttle  110  to pass through. Once the sled structure is positioned behind the carriage path of travel, the shuttle is stopped, and the printer carriage is moved to its position at the service station to receive the pens. After the printer carriage is in its stopped position at area  300 , the shuttle  110  continues its movement toward the rear of the printer to deliver the pens to the carriage. 
     Each pen  30 ,  32  includes datum features used to locate the pen properly in position in the carriage. For example, pen  30  has datum features, e.g.  30 C, protruding from the pen body side walls, e.g. side wall  30 D (FIG.  5 ). The top lid feature  30 A is used to receive a carriage pen latch spring, which is similar is structure and function to the fixed latch spring  160 . Shown in FIG. 9 are the carriage latch springs  202 A,  202 B, as well as the carriage datum features  204 A- 204 D which engage the pen side wall datum features, e.g. feature  30 C. The carriage datum features and the latch springs register the position of the pens in the carriage pen stalls. The carriage also includes electrical interconnect circuitry (not shown) to provide electrical interconnection with the TAB circuit (not shown) on the pens to be able to drive the pen printheads, in a manner well known in the art. The carriage further includes resilient side spring elements  208 A,  209 B and opposed side wall surfaces  208 B,  209 B (FIG. 3) to define pen stalls in the carriage. The spring elements are biased to push the adjacent sides of the pens against the opposed side wall surfaces, to hold the pens in position and into engagement with the carriage datum surfaces  204 A- 204 D (FIG.  9 ). 
     The pens mounted in the shuttle approaches the carriage with a 7° orientation relative to vertical, to position the pen datums above the carriage datums in order to properly assemble the pen into the carriage stall. 
     FIG. 7A shows the shuttle with pens  30 ,  32 , approaching the carriage  200 , which is positioned in the loading position at the service station area  302  (FIG.  9 ). The respective carriage latch springs  202 A,  202 B enters the corresponding top lid datum feature  30 A,  30 B. Once the pen datum enters the corresponding carriage datum feature, the angle of the pen on the shuttle starts changing from the 7° offset to 0°, i.e. to a vertical orientation. As this occurs, the carriage spring is deflected upwardly as it touches the top lid datum feature. As the shuttle continues its rearward motion, the pen drops into position, with the pen datum, e.g.  30 C, behind the carriage datum feature, e.g.  204 A. As the pen angle changes on the shuttle, the corresponding pen plate spring, e.g.  170 A, is compressed to accommodate the change in pen angle. 
     Another aspect of the pen delivery is the rotation of the latch arms  116 ,  118  to release the pen to the carriage. This is accomplished by the pins  116 B,  118 B on each latch arm coming into contact with a rotatable pen link  206 A,  206 B mounted on the carriage. The links are arranged to rotate about a pivot  206 A 1 ,  206 B 1  as the respective pin  116 B,  118 B engages link end  206 A 2 ,  206 B 2 , and are spring-loaded to the position shown in FIG.  7 A. Continued motion of the shuttle  110  in the rearward direction provides a resultant force on the latch arms  116 ,  118  exerted by the links to rotate the latch arms and links outwardly as shown in FIG. 7B, pushing the transverse tab portion  116 A,  118 A away from the corners of the respective pen bodies, releasing the pens to the carriage. 
     FIG. 7C shows the shuttle  110  moving in the reverse direction toward the front of the printer, with the pens transferred to the carriage  200 . Now the latch arms  116 ,  118  have left their contact with the links  206 A,  206 B, and are riding along the side walls of the pens, now secured in the carriage. Once the shuttle  110  is moved sufficiently toward the front of the printer that the latch arms are out of contact with the pens and carriage, the shuttle can be stopped in a rest position, with the wiper blades and capping sled positioned still behind the path of travel of the carriage. The carriage can now be moved to the print area  302  for printing operations. Alternatively, the shuttle can be moved further to the front of the printer, so that the wipers and capping sled are also in front of the carriage travel. 
     FIGS. 8A-8C show a sequence for retrieving the pens from the carriage using the shuttle  110 . The shuttle and carriage are first respectively positioned such that the carriage is in the service station area  300  with the capping sled and wipers behind the carriage. In order to retrieve the pens from the carriage  200 , the shuttle will move toward the rear of the printer toward the carriage. Now the pen links  206 A,  206 B are held back away from contact with the latch arms pins  116 B,  118 B by the pens  30 ,  32  in the carriage stalls. Now the pen latch arm pins  116 B,  118 B will engage respective features  206 A 3 ,  206 B 3  on the pen links  206 A,  206 B instead of features  206 A 2 ,  206 B 2 , allowing the latch arms tab portions  116 A,  118 A to engage the pens (FIG.  8 B). Now the shuttle  110  is driven toward the front of the printer. As this occurs, the latch arms pull the pen free of the carriage, so that the pen is now mounted on the shuttle. The links  206 A,  206 B will return by action of their bias springs to the pen load position shown in FIG.  7 A. 
     The shuttle  110  also carries service station components, to perform wiping, spitting and capping functions. These components include wiper blades  320 A- 320 D,  322 A- 322 D (FIG.  3 ), and a sled structure  340  carrying cap structures  342 A,  342 B for capping pen nozzles for the pens mounted in the printer carriage. The wiper blades are fixed in position on a shuttle floor portion  114 A. Wiper blades are provided to wipe not only the nozzle arrays of the pens, but also the sides of the pens adjacent each side of the nozzle arrays, where ink can collect. For wiping operations, the shuttle is positioned at the rear of the printer, in a position such that the shuttle stalls and latch arms are forward of the carriage path of travel, and the capping sled is behind the carriage path of travel. Now the carriage  200  holding the pens  30 ,  32  is moved to the service position  300 . With the carriage  200  fixed in position, the shuttle motor  231  is actuated to drive the shuttle along its axis, which is transverse to the direction of carriage movement. The wipers engage the pen nozzles arrays to wipe accumulated dried ink and debris from the nozzle plate. Wiper blades for accomplishing this function are known, and are described, e.g. in U.S. Pat. No. 5,455,609. The wipers also engage the sides of the pen adjacent each side of the nozzle array to wipe the adjacent pen surfaces. 
     The shuttle also accommodates a nozzle array ink spitting function. The floor of the printer beneath the service station area is provided with a layer of absorbent material. The shuttle can be positioned so that the open space between the wipers and the capping sled is positioned directly beneath the pen nozzle arrays with the pens supported on the carriage. The pens can energized to spit ink droplets, which are collected by the absorbent material. 
     The capping sled  340  is mounted on four link arms, including link arms  344 A,  344 B (FIGS. 2,  2 B), each of which have one end pivotally mounted on the shuttle subfloor  114 B and the other pivotally mounted to a corner of the sled. A spring guide  348  is also pivotally mounted to the shuttle floor, and carries a coil spring  348 A which engages the bottom of the sled. With this arrangement, the sled can be rotated between a down position (FIG.  2 ), wherein the link arms define a small angle with respect to the shuttle subfloor, and an upright position (FIG. 2B) with the sled  340  elevated above the subfloor and the link arms defining a right angle relative to the floor. A tab feature  346  protrudes upwardly from the sled and is for contacting a rear wall surface  200 A of the carriage. 
     To engage the caps  342 A,  342 B carried on the sled  340  with the pens to cap the pen nozzle arrays, the shuttle is positioned in a rearward position, with the shuttle pen stalls and latch arms located forwardly of the carriage path of travel, and the sled located behind the carriage path of travel. Now the carriage holding the pens is brought to the service station position  300  and stopped. The shuttle motor  131  is driven to move the shuttle toward the front of the printer. The tab feature  346  on the sled engages the back wall surface  200 A of the carriage. As the shuttle continues to move forward, the engagement of the tab with the carriage wall results in rotation of the sled link arms upwardly, lifting the sled into a capping position (FIG.  2 B). As the caps come into contact with the pen printhead area, the spring  348 A allows some compliance movement of the sled relative to the pens. The shuttle is held in this position until the printer is ready for printing or other operation. Now the shuttle will be moved back toward the rear of the printer. This allows the link arms to rotate downwardly, such that the sled  340  drops down, disengaging the caps from the pens. Once the sled is clear of the carriage and pens, the carriage can be moved out of the service station position to the print area  302 . 
     A sled mounted on four pivoted link arms has been used in the past, e.g. the Hewlett-Packard PhotoSmart (TM) photo printer. However, that printer employed a separate motor drive to move the sled transverse to the carriage travel. According to an aspect of this invention, the wiping and capping functions are incorporated in the pen shuttle, so that the drive needed for wiping and capping is shared with the pen shuttle. 
     It will be appreciated that the wiping and capping functions could be separated from the pen shuttle functions. In this case, the pen shuttle would not include wipers and caps, and need only employ the features needed to transfer pens between the front load/unload position and the carriage. 
     FIG. 10 is a control block diagram for the printer  50 . The printer includes a controller  400 , e.g. a microprocessor or ASIC, which is programmed to control the printer operation. The controller receives print jobs from a host  406 , e.g. a personal computer, digital camera, or other source of print data, and acts to activate the media advance system  404  to advance the print medium from the printer input tray through a print zone. The carriage holding the pens  30 ,  32  is driven by the carriage drive system  402  across the print zone, and the controller generates printhead firing commands to cause droplets of ink to be ejected from the respective nozzle arrays  31 ,  33  of the pens  30 ,  32  in a controlled manner. The print medium can be incrementally advanced through the print zone by the media advance system  404  to position fresh portions of the medium at the print zone after completion of carriage swaths. Upon completion of a print job, the media advance system moves the medium to the output tray of the printer. The controller drives the shuttle drive motor  131  at appropriate times in response to front panel switches  56 , to load or unload a pen from the carriage. Alternatively, commands to initiate a load/unload operation could be generated by the controller automatically, say in response to an out-of-ink determination. 
     It is understood that the above-described embodiments are merely illustrative of the possible specific embodiments which may represent principles of the present invention. Other arrangements may readily be devised in accordance with these principles by those skilled in the art without departing from the scope and spirit of the invention.