Abstract:
A fluid containment system includes an ink depository and a hood secured thereto. The hood includes an ink redirection structure for directing ink emitted from a printhead through a constrictive conduit into the ink depository.

Description:
BACKGROUND 
     Printing mechanisms, such as inkjet printers, may use pens, which shoot drops of liquid colorant, referred to generally herein as “ink,” onto a print medium, such as a page of paper. Each pen may have a printhead formed with very small nozzles through which the ink drops are fired. To print an image, the printhead may be propelled back and forth across the page, shooting drops of ink in a desired pattern as it moves. The particular ink ejection mechanism within the printhead may be implemented in a variety of different ways, such as by piezo-electric or thermal printhead technology. 
     To clean and protect the printhead, also called servicing or maintenance of the printhead, a service station mechanism may be mounted within the printer. During cleaning the printhead may be moved over the service station and ink may be ejected or “purged” from the printhead nozzles toward a spittoon or ink collection chamber of the service station. The ejected ink may combine with surrounding air to create an ink aerosol that is not easily contained with the spittoon. The uncontained ink aerosol may damage internal components of the printing mechanism or contaminate sites within the printing mechanism such as the input or outputs trays, or print media held therein. In the case of color printing mechanisms, an ink aerosol from one colored ink printhead may emerge from the spittoon and contaminate an ink printhead of a different colored ink, thereby reducing the print quality of each image printed thereafter. 
     SUMMARY OF THE INVENTION 
     A fluid containment system includes an ink depository and a hood secured thereto. The hood includes an ink redirection structure for directing ink emitted from a printhead through a constrictive conduit into the ink depository. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of one embodiment of a printing mechanism that includes a service station including an ink collection reservoir with a hood positioned thereon. 
         FIG. 2  is a side cross sectional view of one embodiment of the hood and reservoir of the printing mechanism of FIG.  1 . 
         FIG. 3  is a side cross sectional view of another embodiment of the hood and reservoir of the printing mechanism of FIG.  1 . 
         FIG. 4  is a side cross sectional view of another embodiment of the hood and reservoir of the printing mechanism of FIG.  1 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  illustrates one embodiment of a printing mechanism, here shown as a printer  20 , which may be used for the printing of business reports, correspondence, desktop publishing, and the like, in an industrial, office, home or other environment. A variety of printing mechanisms is commercially available, such as inkjet printers and laser printers, for example. Some of the printing mechanisms that may use embodiments of the present invention include plotters, portable printing units, copiers, cameras, video printers, and facsimile machines, to name a few. For convenience, the concepts of the printing mechanism are illustrated in the environment of an inkjet printer  20 . 
     While it is apparent that the printer components may vary from model to model, inkjet printer  20  may include a chassis  22  surrounded by a housing, also called a body or a casing enclosure  24 , which may be manufactured of plastic. A sheet or sheets of print media may be fed through a print zone  26  and beneath a first printhead  28 , also referred to as a printing means and an ink ejection device, and a second printhead  30 . The one or more printheads may be supported on a printhead carriage  32  which is supported on a carriage rod  34  extending through the housing and defining a scanning axis  36 . The print media sheet  38  or sheets may be any type of suitable material, such as paper, card-stock, cardboard, transparencies, mylar, and the like, but for convenience, the illustrated embodiment is described using paper as the print medium. 
     In the embodiment shown, sheet  38  is shown exiting print zone  26  and being deposited on an output tray  40  having a sliding length adjustment lever  42 . Positioned below output tray  40  is an input tray  44  including a length adjustment device, such as a sliding length adjustment lever  46  and a width adjustment device, such as a sliding width adjustment lever  48 , for accommodating different sizes of print media, including letter, legal, A-4, and envelopes, for example. 
     An actuation device, such as a motor  50  (shown schematically in dash lines), may be positioned within housing  24  and may operate to move printhead carriage  32  along carriage rod  34 , in the direction of scanning axis  36 , from print zone  26  into a servicing region  52 . For ease of illustration, printhead carriage  32  is shown in print zone  26  so that servicing region  52  may be viewed. A capping station, not shown, may be separately positioned on an opposite side of the printer, i.e., along carriage rod  34  and adjacent motor  50 . A printer controller, illustrated schematically as a microprocessor  54 , may be positioned within housing  24  and may receive instructions from a host device, typically a computer, such as a personal computer (not shown) for operating motor  50  and printheads  28  and  30 . Many of the printer controller functions may be performed by the host computer, by the electronics on board the printer, or by interactions therebetween. As used herein, the term “printer controller  54 ” encompasses these functions, whether performed by the host computer, the printer, an intermediary device therebetween, or by a combined, interaction of such elements. The printer controller  54  may also operate in response to user inputs provided through a key pad (not shown) located on an exterior of housing  24 . A monitor coupled to the computer host may be used to display visual information to an operator, such as the printer status or a particular program being run on the host computer. 
     Still referring to  FIG. 1 , service region  52  may comprise a service station  56 , also referred to herein as a cleaning station or a maintenance station, movable into position adjacent printheads  28  and  30  when the printheads are moved into the service region. Service station  56 , also referred to as a servicing means, may include a support sled  58  that movably supports an ink receiving means such as a first spittoon  60 , which functions as an ink collection chamber. The support sled  58  may include wipers, wiper scrapers, and/or absorbers, not shown, that may be moved back and forth across the printheads to service the printheads  28  and  30 . Actuation of the sled  58  may be accomplished with a drive gear and a mating gear rack, not shown, that may be positioned beneath the support sled. The support sled  58  may be held stationary adjacent the printhead  28  during “spitting” by the pens so that the printhead is properly aligned with its corresponding spittoon. In the embodiment shown, the support sled  58  further includes a second spittoon  62  so that each of the printheads will align with a corresponding spittoon during the servicing routine. Each of the spittoons  60  and  62  may include a surface directing means, such as hoods  64  and  66 , respectively, that change the trajectories of ink droplets emitted from printheads  20  and  30 . 
       FIG. 2  illustrates a side cross sectional view of one embodiment of the printing mechanism of  FIG. 1 , wherein a nozzle orifice plate  68  of first printhead  28  is positioned in servicing region  52 , above and aligned with an upper hood opening  70  of first hood  64 . Upper hood opening  70  has a perimeter  71  which defines an area A 1  that may be sized and shaped to efficiently capture ink particles ejected from printhead  28 . As shown in  FIG. 2 , hood  64  includes an upper opening  70  defined by a guide structure  83  and a stop structure  82 . Upper guide structure  83  has an upper guide surface  80  and an opposed underside surface  81 . Stop structure  82  includes an upper surface  87  and an underside surface  89 . Ink particles ejected from printhead  28  tend to form an aerosol that undesirably may become deposited on various components of printer  20 . Therefore, capturing ink particles ejected from printhead  28  during servicing of the printhead is very desirable. During servicing, area A 1  is generally positioned proximate to printhead  28  so that ink particles ejected from printhead  28  may ejected through opening  70  of hood  64 . During servicing of the printhead  28 , area A 1  is generally oriented perpendicularly to directional ray  90 , and is shown edge-on in FIG.  2 . Ray  90  is also coincident with a normal of area A 1 , where a normal is defined as a line that is perpendicular to the plane defined by area A 1 . Hood  64  is secured to depository opening  72 , of spittoon  60 , and funnels ink particles ejected from the printhead  28  during servicing into reservoir  76  of spittoon  60 . Opening  72  has a perimeter  74  that defines an area A 2  of opening  72  which is generally perpendicular to direction ray  90 . Area A 2  may be quite large compared to area A 1 , and is shown edge-on in FIG.  2 . By way of example, area A 2  may be more than four times larger than the area A 1 . 
     At least fifty percent, and in particular, approximately seventy five percent, of the area A 2  may be blocked by the underside surface  81  of guide structure  83 . By way of example, at least eighty percent, and in particular, approximately ninety five percent, of the area A 2  may be occluded or blocked by a combination of underside surface  81  and stop surface  82 . The difference in size between areas A 1  and A 2  facilitates capturing or trapping any ink particles or ink aerosols that enter reservoir  76  of spittoon  60 , as described below. 
     Guide structure  83  and stop structure  82  are stationary with respect to hood  64 , and do not pivot or rotate within the hood. Hood  64  includes underside surface  89  and deflection surface  91 . Surface  89  generally meets and is coterminous with deflection surface  91  at an angles of about 90 degrees, although the scope of the invention includes joining these surfaces at other angles, as may be required to suit the needs of a particular application. Underside surface  81  and deflection surface  91  collectively define a lower hood opening  84  having a perimeter  86 . Perimeter  86  defines area A 3  of opening  84 , where area A 3  is represented edge-on as a line in FIG.  2 . Surfaces  80  and  89  extend between opening  70  and opening  84  to form a progressively narrow or constricted conduit  88 . Area A 1  of upper hood opening  70  may be large compared to area A 3  of lower hood opening  84  and, in particular, the area A 1  may be more than two times larger than area A 3 . Area A 2  may be eight times larger than area A 3 . Thus, it may be appreciated that hood  64  defines a funnel shaped, constricted conduit  88  that extends and becomes progressively more restricted from opening  70  to opening  84 . The underside surface  89  of stop structure  82  serves as a ridge that helps to inhibit the flow of any ink particles  78  out of hood  64  after they enter channel  88 . 
     Still referring to  FIG. 2 , during maintenance of printhead  28 , the printhead may purge or eject ink particles  78  along a trajectory represented by directional ray  90 , which may be oriented perpendicularly with respect to nozzle orifice plate  68  and to a lower surface  92  of reservoir  76  of spittoon  60 . If ink particles  78  are allowed to directly enter reservoir  76  of spittoon  60  without hood  64  positioned thereon, the ink particles  78  may strike lower surface  92  of the spittoon and be directed back out of the opening  70  the hood  64 . The ink particles  78  may contaminate and possibly damage components of the printer, thereby reducing future print quality. Therefore, containing ink particles  78  in reservoir  76 , especially when the ink particles are in an aerosol state, is very desirable. 
     In the embodiment shown in  FIG. 2 , stop structure  82  is shown by way of example to be oriented generally perpendicularly with respect to directional ray  90 . However, the scope of the invention also allows for stop structure  82  to be positioned at an angle in the range of about one to ninety degrees with respect to ray  90 , as required to suit the needs of a particular application. 
     In order to reduce or inhibit the quantity and/or volume of ink particles that may escape from spittoon  60 , guide surface  80  of guide structure  83  redirects movement of ink particles  78  from a trajectory along ink directional ray  90  to a second trajectory or direction that is different from ray  90 , as for example, along redirection ray  94 . Ink particles  78  may enter spittoon  60  along a ray that is other than perpendicular to lower surface  92  of the spittoon so that the ink particles  78  are not easily deflected upwardly and out of the spittoon. In the embodiment shown, guide surface  80  is inclined with respect to directional ray  90  such that guide surface  80  defines an acute angle  96  therebetween. Angle  96  may be in a range of one to eighty nine degrees, but may more typically be in a range of forty five to eighty nine degrees so as to direct the ink particles  78  along a trajectory oriented downwardly and away from upper hood opening  70 , as for example, in the direction of redirection ray  94 . Any ink particles  78  that are deflected off surface  80  in the direction of ray  90  and traveling fast enough, may then be deflected off surface  91  of hood  64 , and then be directed into reservoir  76  along directional ray  97 . Guide surface  80  of guide structure  83  is oriented at an inclined angle with respect to ink direction ray  90  and surface  92  so that when the ink particles  78  enter spittoon  60 , the ink particles do not readily escape from the spittoon, but instead are captured or trapped in reservoir  76 . 
     Lower hood opening  84  may be offset from upper hood opening  70 , with respect to axis a-a that is parallel to a normal of area A 1 . Such an offset hinders ink particles  78  from escaping reservoir  76  of the spittoon  60 . In particular, opening  84  and opening  70  may be offset from one another such that opening  72  of the spittoon is significantly blocked when viewed from inside the spittoon along a direction parallel and opposite to the direction of ray  90 . Due to the relatively smaller size of area A 3  of lower hood opening  86  relative to the size of area A 2  of spittoon opening  72 , even if ink particles  78  are deflected upwardly out of spittoon  60 , the ink particles have a strong possibility of contacting an underside  98  of hood  64 , rather than escape through restricted opening  84 . Thus, particles that enter reservoir  76  are likely to be contained therein. Any particles that may escape from reservoir  76  back into conduit  88  may be prevented from escaping hood  64  by underside  89  of stop structure  82 . 
     The spittoon hood  64  as shown reduces ink particle contamination within printer  20  in two distinct manners. Guide surface  80  of hood  64  redirects ink particles  78  ejected from printhead  28  so that ink particles  78  are not readily deflected upwardly and out of spittoon  60 . Second, redirection surface  80  of hood  64  guides ink particles  78  through restricted opening  84  in the hood and into the large interior space of reservoir  76  of spittoon  60 . The configuration of underside surface  81  of guide structure  83  and underside surface  89  of stop surface  82  inhibit the escape of ink particles  78  out of reservoir  76  and/or through hood  64 . Moreover, in the embodiment shown, hood  64  provides a first opening  84  and another opening  70 . Openings  70  and  84  are offset from one another with respect to axis a-a. The offset relation of openings  84  and  70  further inhibits escape of ink particles  78  from the spittoon  60 . 
     The positions and orientations of surfaces  81  and  82  facilitate generally one-way flow of ink particles  78  into collection chamber  60 , while inhibiting the flow of the ink particles  78  back through the hood or chimney  64 . Due to the small size of restricted opening  86  of spittoon  60 , the ink particles  78  that enter reservoir  76  tend to become trapped therein. The combination of angled surfaces of hood  64  provides a virtual “lid” for the reservoir  76  of spittoon  60  collection chamber so that ink particle contamination of the printer and/or printer components is markedly reduced. 
       FIG. 3  illustrates a side cross sectional view of another embodiment of the printing mechanism of FIG.  1 . In this embodiment, inclined stop surface  82  defines an angle  100  with respect to directional ray  90 . Guide surface  80  and stop surface  82  form a funnel-shaped, i.e., constricted conduit  88  for channeling ink particles  78  that becomes increasingly more constricted as it extends from upper hood opening  70  towards lower hood opening  84 . The surface  80  redirects ink particles  78  from a trajectory along direction ray  90  to a trajectory along redirection ray  94 . Then, surface  82  may deflect the ink particles  78  toward restricted hood opening  84  in the direction of ray  97  and into reservoir  76 . Hood opening  70  and hood opening  84  are offset from one another, i.e., not aligned with one another along a direction parallel to axis a-a so that ink particles  78  are significantly hindered from escaping reservoir  76  of spittoon  60 , and generally are trapped therein. 
       FIG. 4  illustrates a side cross sectional view of another embodiment of the printing mechanism of FIG.  1 . In this embodiment, stop surface  82  may be generally parallel to lower surface  92  of spittoon  60  and slightly longer than the corresponding length of stop surface  82  shown in FIG.  1 . Upper cap opening  70  of hood  64 , therefore, when viewed along a direction parallel to axis a-a is generally offset from lower cap opening  84  of the hood. Thus, when viewed along axis a-a in a direction generally perpendicular to lower surface  92  of the spittoon  60 , portions of opening  70  and  84  overlap one another. Accordingly, in this embodiment, there is no direct linear path of escape for ink particles  78  out of spittoon  60  along a linear path parallel to axis a-a 
     Herein described are embodiments of a printing mechanism  20  that include a service station  56  having an ink depository  60  adapted for receiving ink particles  78  purged from a printhead  28  during servicing thereof and a hood  64  secured to the ink depository. The hood  64  defines a stationary ink redirection surface  80  for changing a direction of movement of ink emitted from the printhead so as to trap the ink particles  78  within the ink reservoir. 
     Although specific embodiments have been illustrated and described herein for purposes of description of the preferred embodiment, it will be appreciated by those of ordinary skill in the art that a wide variety of alternate and/or equivalent implementations calculated to achieve the same purposes may be substituted for the specific embodiments shown and described herein without departing from the scope of the present invention. Those with skill in the chemical, mechanical, electro-mechanical, electrical, and computer arts will readily appreciate that the present invention may be implemented in a very wide variety of embodiments. This application is intended to cover any adaptations or variations of the preferred embodiments discussed herein. Therefore, it is manifestly intended that this invention be limited only by the claims and the equivalents thereof.