Abstract:
A removable safety cap ( 10 ) for use with an ink cartridge or other fluid holding container having a nozzle ( 34 ) extending from the dispensing end. The safety cap ( 10 ) prevents the flow of ink out of the cartridge or, if ink escapes past the dispensing nozzle seal, prevents the flow of ink outside the cap ( 10 ). The cap ( 10 ) also enables the ink cartridge to be set upright with the dispensing end down without the need for a nest or fixture to help support the cartridge.

Description:
BACKGROUND  
         [0001]    1. Field of the Invention  
           [0002]    This patent relates to a safety cap to be placed over the nozzle of a fluid-dispensing cartridge. More particularly, this patent relates to a safety cap to be placed over the dispensing fitment of an ink cartridge of the type used in automatic lithographic printing presses.  
           [0003]    2. Description of the Related Art  
           [0004]    Modern ink cartridges for printing presses typically comprise a hollow tubular body, a moveable plunger inserted into one end, and a stationary dispensing fitment attached to the opposite end. The dispensing fitment covers the dispensing end of the tubular body and has a built-in nozzle for opening and closing the cartridge. Ink is extruded through the nozzle when the plunger is forced toward the dispensing end either manually or, more commonly, by pneumatic pressure. Typically, the cartridge is filled with ink by placing the cartridge with the dispensing end down, adding the ink through the open plunger end, then inserting the plunger. It is also desirable to ship and store ink cartridges with the dispensing end down.  
           [0005]    The dispensing fitment is mounted in sealing engagement within the dispensing (top) end of the tubular body and comprises a covering portion and a nozzle extending from the covering portion. The nozzle serves several functions: (1) it guides the flow of ink from the cartridge when the plunger is activated; (2) it prevents the flow of ink at all other times, including during filling, transportation, storage, and installation of the cartridge on the printing press; and (3) it prevents the introduction of air into the cartridge.  
           [0006]    A potential problem with conventional ink cartridges is that, during use, the nozzles can leak ink onto the outside of the dispensing fitment. The ink can then dry and flake off, contaminating the ink reservoir beneath the cartridge.  
           [0007]    Another potential problem with conventional ink cartridges is that, because of the protruding nozzles, they cannot be stood on their dispensing end for filling, shipping or storage purposes without using a nest or fixture to keep the cartridge upright and stable.  
           [0008]    Another potential problem with conventional ink cartridges is the introduction of air into the cartridge. If an ink cartridge is stored or shipped with the dispensing end up, the ink can shift down due to gravity. If the seal on the dispensing nozzle is not airtight, this shifting can pull air into the cartridge and cause the ink to start curing. Curing reduces the quality of the ink and increases the risk of poor quality dispensing.  
           [0009]    Thus it is an object of the present invention to provide a safety cap for use with ink cartridges that prevents the flow of ink past the dispensing nozzle seal.  
           [0010]    Another object of the present invention is to provide a safety cap that prevents the flow of ink outside the cap if the ink escapes past the dispensing nozzle seal.  
           [0011]    Still another object of the invention is to provide a safety cap that enables an ink cartridge to be set upright with the dispensing end down without the need for a nest or fixture to help support the cartridge.  
           [0012]    Another object of the invention is to provide a safety cap that keeps the dispensing nozzle clean and protects it from damage during shipping and handling.  
           [0013]    Further and additional objects will appear from the description and accompanying drawings.  
         SUMMARY OF THE INVENTION  
         [0014]    The present invention is a safety cap for use with ink cartridges of the type having a nozzle extending from a dispensing fitment affixed to the dispensing end. The safety cap prevents the flow of ink out of the cartridge or, if ink escapes past the dispensing nozzle seal, prevents the flow of ink outside the cap. The cap also enables the ink cartridge to be set upright with the dispensing end down without the need for a nest or fixture to help support the cartridge.  
           [0015]    The cap comprises a hub portion, a substantially cylindrical outer wall surrounding the hub portion, and an annular wall connecting the hub portion to the outer wall. The hub portion is configured to fit closely over the dispensing fitment nozzle and comprises a dome-shaped top wall and a downwardly extending skirt portion terminating in a sealing lip. The sealing lip is adapted to form a seal with the dispensing fitment when the safety cap in installed onto the dispensing fitment. The outer wall of the cap has a top rim upon which the cartridge can stand during filling, storage and transportation. The skirt portion of the hub has inwardly extending locking elements adapted to be engaged by and disengaged from complementary locking elements on the dispensing fitment.  
       
    
    
     THE DRAWINGS  
       [0016]    [0016]FIG. 1 is a top perspective view of a safety cap according to the present invention.  
         [0017]    [0017]FIG. 2 is a bottom perspective view of the safety cap of FIG. 1.  
         [0018]    [0018]FIG. 3 is a cutaway perspective view of the safety cap of FIG. 1, shown with an ink cartridge dispensing fitment and plunger.  
         [0019]    [0019]FIG. 4 is a cross-sectional view of the safety cap, dispensing fitment and plunger of FIG. 3.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0020]    Turning to the drawings, there is shown in FIGS. 1-2 one embodiment of the present invention, a safety cap  10  for use with an ink cartridge of the type used in lithographic printing presses or other fluid-dispensing container. As shown in FIGS. 3 and 4, the safety cap  10  has locking elements  12  or other attachment means that can be used to attach the safety cap  10  to a dispensing fitment  14 . A plunger  16  and a cartridge body (not shown) make up the other components of the assembled ink cartridge.  
         [0021]    In the assembled ink cartridge, the cartridge body holds a supply of extrudable ink and has a dispensing end and a plunger end. The plunger  16  is inserted into the plunger end and serves as a piston that is driven through the cartridge body, typically by pneumatic force, to extrude ink through the nozzle portion of the dispensing fitment  14 . To minimize wasted ink, the plunger  16  mates closely with the dispensing fitment  14  when the plunger  16  is driven the full length of the ink cartridge. The dispensing fitment  14  is firmly attached to or made part of the dispensing end of the cartridge.  
         [0022]    Although the dispensing fitment  14  may take many forms, the preferred embodiment will now be described. Turning to FIG. 4, it will be noted that the dispensing fitment  14  comprises two separately molded plastic parts: an inner (mating) component  18  and an outer component  20 .  
         [0023]    The inner mating component  18  comprises a cylindrical sidewall  22  and a dome-shaped sealing portion  24  connected to the sidewall  22  by bridges  26 . As described in more detail below, ink flows through the spaces between the bridges when the dispensing nozzle is forced open by pressure from the ink. The inner component  18  is affixed to the inside of the outer component  20  and mates closely therewith to prevent ink from getting between the inner and outer components.  
         [0024]    The outer component  20  comprises a covering portion  30  for covering the dispensing end of the ink cartridge, a skirt  32  extending downward from the periphery of the covering portion  30 , and an upwardly extending nozzle portion  34  mounted over a centrally disposed aperture in the covering portion  30 . The skirt  32  fits snugly into the dispensing end of the ink cartridge body (not shown). A flange  36  extends radially outward from the top of the skirt  32  to halt the insertion of the dispensing fitment  14  into the cartridge body.  
         [0025]    The nozzle portion  34  of the dispensing fitment  14  comprises a sidewall  38  extending upward from the covering portion  30  and an annular flexible valve portion  40  extending radially inward from the top edge of the nozzle sidewall  38 , terminating in a rigid annular rim  42 . Locking threads  44  project outwardly from the nozzle sidewall  38  and are configured to receive the safety cap  10 .  
         [0026]    The flexible valve portion  40  of the nozzle  34  is sufficiently thin and has a geometry that allows it to flex under pressure from a closed position to an open position. The pressure is supplied by the ink when the plunger  16  is driven toward the dispensing end of the cartridge. In the closed position shown in FIG. 4, the annular rim  42  presses against the dome-shaped sealing portion  24  of the inner component  18  to seal off the ink cartridge. This seal is referred to hereinafter as the primary seal. In the open position, the flexible portion  40  flexes upward and outward to create an annular opening between the rim  42  and the sealing portion  24  through which ink can flow.  
         [0027]    Although the dispensing fitment  14  just described has a primary seal designed to prevent the leakage of ink when there is no internal pressure placed on the flexible valve  40  by the ink inside the cartridge, it has been found advantageous to provide the ink cartridge assembly with a safety cap to further prevent ink leakage and to provide a means to enable the ink cartridge to be stood on its dispensing end. The safety cap  10  of the present invention fulfills this need.  
         [0028]    The safety cap  10  preferably is a one-piece molded plastic part, and in the preferred embodiment comprises a centrally disposed hub portion  50 , an annular wall  52  and a substantially cylindrical outer wall  54 . The annular wall  52  extends radially outward from the hub portion  18  to the outer wall  54 . Optional evenly spaced fins  56  extend radially outward from the hub portion  50  to the outer wall  54  to provide additional structural support. Other structures may be used instead of or in addition to the fins  56  to help support and stabilize the safety cap  10 , such as concentrically spaced stiffening rings.  
         [0029]    The hub portion  50  is configured to fit closely over the dispensing fitment nozzle  34 , and comprises a dome- shaped top wall  60  and a downwardly extending skirt portion  62  that terminates in a sealing lip  64 . As explained further below, the sealing lip  64  forms a seal against the dispensing fitment covering portion  30  when the safety cap  10  is installed onto the dispensing fitment  14 .  
         [0030]    The safety cap locking elements  12  are in the form of inwardly projecting detents and are evenly distributed around the inside wall of the skirt portion  62 . To install the safety cap  10  onto the dispensing fitment  14 , the cap  10  is oriented such that the locking detents  12  are located above the spaces between the nozzle locking threads  44 , pushed in an axial direction onto the dispensing fitment  14  and rotated until the locking detents  12  are fully engaged by the threads  44 .  
         [0031]    When the safety cap  10  is so installed, the hub portion top wall  60  presses down on the flexible annular portion  40  of the nozzle  34  to force the annular rim  42  against the sealing portion  24 , thereby further insuring that ink does not leak from the nozzle  44 . In case this primary seal leaks, the annular area  45  where the top wall  60  of the safety cap  10  presses against the annular portion  40  acts as a secondary seal.  
         [0032]    When cartridges are stored with the dispensing end up, the contents can shift down due to gravity. If the nozzle is not sealed airtight, this shifting can pull air into the cartridge and ruin the ink. The pressure placed on the flexible annular portion  40  by the hub portion top wall  60  also insures that air does not get pulled into the cartridge.  
         [0033]    The safety cap  10  forms a third seal with the dispensing fitment  14  at the annular region near the base of the nozzle  34  where sealing lip  64  contacts the covering portion  30  of the dispensing fitment  14 . Thus, the safety cap  10  and dispensing fitment  14  cooperate to form two additional seals to prevent the flow of ink outside the cap  10 .  
         [0034]    The outer wall  54  of the safety cap  10  has a top rim  66  that defines a plane above which the hub portion  50  does not extend, so that the cartridge can be placed upright on this rim  66  with the dispensing end down during filling, shipping and storage. The diameter of the outer wall top rim  66  should be large enough to provide a stable base for the ink cartridge when it is placed on its dispensing end, and preferably is about the same as the diameter of the ink cartridge itself.  
         [0035]    The lower portion  68  of the outer wall  54  fits over the dispensing fitment covering portion  30  near its periphery to help protect the fitment from side impacts. Gripping elements  70  in the form of vertically oriented ridges located on the outer surface of the outer wall  54  facilitate rotating the safety cap  10 .  
         [0036]    Thus there has been described a safety cap  10  for an ink cartridge or the like that installs over a dispensing fitment  14  of the type described herein or over a similar fitment. The safety cap  10  performs three primary functions: (1) it prevents ink from leaking out of the cartridge when the nozzle  34  is in the closed position by putting pressure on the dispensing mechanism, (2) it prevents air from getting pulled into the cartridge if the cartridge is stored dispenser end up, and (3) it allows the cartridge to be stood on its dispensing end during shipping, filling, transporting and storage.  
         [0037]    Other modifications and alternative embodiments of the invention are contemplated which do not depart from the spirit and scope of the invention as defined by the foregoing teachings and appended claims. It is intended that the claims cover all such modifications that fall within their scope.