Abstract:
Embodiments of the present invention comprise one-part elastomeric valves which are manipulated after molding to preload the valve seal. The valves maintain positive seal until a fluidic pressure or mechanical force is applied to open the valve. The valves return to a closed state after the pressure or force is removed.

Description:
TECHNICAL FIELD OF THE INVENTION 
     The present invention relates generally to valves for controlling fluid flow, and more particularly to valves formed of an elastomeric material. 
     BACKGROUND OF THE INVENTION 
     Fluidic valves are well known in the art, and are utilized in a wide range of applications. For example, fluidic valves are often utilized to control ink flow in printer systems. Fluidic valves may range from simple, inexpensive one-part structures to complex assemblies. 
     Inexpensive valves may be simple non-loaded structures or slightly more complex interface-reliant valves. The non-loaded type, such as “duckbill” valves, are prone to leaking at small pressure differences across the valve. The interface-reliant type, such as “umbrella” valves, require a sealing surface other than the valve itself, which requires additional components to make the seal with mating components. Another interface-reliant valve is the slit septum type, in which a needle penetrates a normally closed septum to establish fluid flow. This type of valve is often prone to leaks and requires a high degree of alignment between the needle and valve. Assuring precise alignment often adds cost to a fluid system. 
     Conventional fluidic interconnect valves which have preloaded seals are typically multi-part. The added complexity may include a ball, a spring, or a flap, or other components. Where a large number of valves is required in a fluid system, such as in a printer system with multiple ink colors, the added complexity of such valves may be prohibitively expensive. 
     There is therefore a need for fluidic valves that provide robust fluid seals at low cost. 
     SUMMARY OF THE INVENTION 
     Embodiments of the present invention comprise one-part elastomeric valves which are manipulated after molding to preload the valve seal. The valves maintain positive seal until a fluidic pressure or mechanical force is applied to open the valve. The valves return to a closed state after the pressure or force is removed. 
     Other aspects and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front perspective view of an exemplary embodiment of the valve of the present invention after molding, but prior to preloading; 
     FIG. 2 is a rear perspective view of an exemplary embodiment of the valve of the present invention after molding, but prior to preloading; 
     FIG. 3 is a cross sectional view of an exemplary embodiment of the valve of the present invention along line A—A of FIG. 2; 
     FIG. 4 is a cross sectional view of an exemplary embodiment of the valve of the present invention after preloading and installation; 
     FIG. 5 is a cross sectional view of an exemplary embodiment of the valve of the present invention showing a needle engaging the valve and sealing to the valve lip; and 
     FIG. 6 is a cross sectional view of an exemplary embodiment of the valve of the present invention showing a needle opening the valve. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIGS. 1 and 2 are front and rear perspective views, respectively, of an exemplary embodiment of the valve  100  of the present invention, shown before the valve has been manipulated for preloading. The valve is preferably integrally molded of a low durometer elastometer. The valve comprises a lip portion  110 ; a first mounting seal  120 ; a mounting groove  130 ; a second mounting seal  140 ; and a rear portion  150  including a plurality of fluid passages  160 . The rear portion also includes a stopper member  155 , which is further discussed with respect to FIG. 3 below. The lip portion  110  of the valve is formed as a truncated cone with an orifice  112 ; the lip is later manipulated to provide a preloaded seal, as also discussed below. 
     The preferred material for forming the valve is an EPDM (ethylene polypropylene diene monomer)/butyl blend with a durometer of approximately 50-70. Other resilient elastomeric materials, such as silicone rubber, may also be used. The material characteristics will vary with the specific design and intended application of the valve. 
     FIG. 3 is a cross sectional view of an exemplary embodiment of the valve of the present invention along line A—A of FIG.  2 . Stopper member  155  extends forward with a cylindrical wall  158  and a contact face  157 . To form the completed valve, the conical lip  110  is pushed into the orifice  112  until the inverted lip forms a seal with the cylindrical wall  158  of the stopper, as shown in FIG.  4 . 
     FIG. 4 is a cross sectional view of an exemplary embodiment of the valve of the present invention after preloading and installation. For installation of the valve into a fluid system, such as an ink delivery system in a printer, the exemplary embodiment of the valve is inserted into a round opening formed in a flat surface  210 , such as the wall of an ink container. The first and second mounting seals  120  and  140  contact the two sides of the flat surface  210 , providing fluid tight seals. 
     FIG. 5 is a cross sectional view of an exemplary embodiment of the valve of the present invention showing a hollow needle  310  beginning to engaging the valve and sealing to the valve lip  110 ′. The hollow needle may typically be made of molded plastic, with one or more openings  312  at the tip for fluid flow, and a protuberance  314  for engaging the contact face  157  of the valve. 
     An advantage of the present valve design over previous “slit septum” designs is that it enables the use of relatively inexpensive plastic needles. With slit septums, the needle must be very slender, and therefore typically made of metal. With the valve of the present invention, the need to minimize the diameter of the needle diameter is obviated, and less expensive plastic needles may be employed. The valve of the present invention thus allows an overall reduction is system cost. 
     FIG. 6 is a cross sectional view of an exemplary embodiment of the valve of the present invention showing a needle  300  opening the valve  100 . The needle urges the valve lips  110 ′ apart and resiliently forces the valve stopper  155  back, creating fluid passageways around the stopper and through the fluid passageways  160 . Removal of the needle closes the valve via the elastomeric rebound properties of the valve parent material. 
     The valve of the present invention is thus a low cost single component mechanisim which is easy to manufacture and assemble into a fluidic system. A further advantage of the valve of the present invention is the simplicity of installation, resulting in further cost savings. 
     The above is a detailed description of particular embodiments of the invention. It is recognized that departures from the disclosed embodiments may be within the scope of this invention and that obvious modifications will occur to a person skilled in the art. It is the intent of the applicant that the invention include alternative implementations known in the art that perform the same functions as those disclosed. This specification should not be construed to unduly narrow the full scope of protection to which the invention is entitled. 
     The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or acts for performing the functions in combination with other claimed elements as specifically claimed.