Abstract:
A printhead assembly that includes a partially-etched port structured to be opened by application of pressure to the port area, one or more leaflets being depressed into an internal chamber communicating with the open port.

Description:
BACKGROUND 
     Drop on demand ink jet technology for producing printed media has been employed in commercial products such as printers, plotters, and facsimile machines. Generally, an ink jet image is formed by selective placement on a receiver surface of ink drops emitted by a plurality of drop generators implemented, for example, in a printhead comprising a stack of metal plates having fluidic chambers and channels formed therein (commonly referred to as a jet stack assembly). Ink is stored in an ink reservoir and loaded into the printhead assembly through ports in a diaphragm plate on the back side of the printhead assembly. 
     In printhead assembly manufacture, ports are formed in the diaphragm prior to incorporation of the diaphragm into the jet stack assembly. Ports typically are formed by etching through the diaphragm. 
     Some printhead assembly manufacturing methods may require that the diaphragm have no open ports during the processing of the printhead. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a cross-sectional side view diagram of a jet stack assembly for a printhead. 
         FIG. 2  is a plan view diagram of the jet stack assembly of  FIG. 1 . 
         FIG. 3  is a plan view diagram of a first embodiment of a partially-etched port. 
         FIG. 4  is a plan view diagram of the first embodiment partially-etched port after piercing. 
         FIG. 5  is a cross-sectional side view diagram of the partially-etched port of  FIG. 4  after piercing. 
         FIG. 6  is a plan view diagram of a second embodiment of a partially-etched port. 
         FIG. 7  is a plan view diagram of the second embodiment partially-etched port after piercing. 
         FIG. 8  is a cross-sectional side view diagram of the partially-etched port of  FIG. 7  after piercing. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1 and 2  are cross-sectional side and plan view diagrams, respectively, of a printhead assembly  1  for a printhead. The printhead assembly  1  includes a diaphragm plate  10 , aperture plate  20 , and body  30  intermediate the aperture plate  20  and diaphragm plate  10 . The printhead assembly  1  has a thickness T S , which can be generally on the order of 90 mils. 
     By way of illustrative example, a diaphragm plate (or diaphragm)  10  of a printhead assembly  1  generally includes ports  40  permitting communication of a reservoir (not shown) and chambers  42  within the printhead assembly  1 . Ports  40  can be curved in shape, with an exemplary circular port having a diameter D P  of no less than 10 mils but not greater than 250 mils. 
       FIG. 3  is a plan view diagram of a first embodiment partially-etched port trace  50  formed on a diaphragm  10  of a printhead assembly  1 . By way of illustrative example, this embodiment includes a curved port perimeter or port boundary having a partially-etched arc  60  comprising a substantial portion thereof partially-etched into the diaphragm plate  10  material. A non-etched hinge region  62  remains at the remaining portion of the curved port boundary. In this embodiment, the partially-etched arc  60  comprises about 90% of the port boundary, although a greater or lesser percentage may be efficaciously employed. 
       FIGS. 4 and 5  are plan and cross-sectional side view diagrams showing the port  40  of  FIG. 3  after piercing. When pressure is applied to the port area  50 , the diaphragm plate  10  fractures along the partially-etched arc  60 . A port  40  is opened thereby and a leaflet  52  is formed by the depressed or pierced portion of the diaphragm plate  10 . 
     The leaflet  52  generally is disposed at an angle to the diaphragm plate  10  after depression. It is readily appreciated that the leaflet  52  can be deflected out of the plane of the diaphragm plate  10 , while the non-etched hinge region  62  retains the leaflet  52  and thereby prevents it from breaking off. 
     The material used to make the diaphragm plate  10  may permit the leaflet  52  to rebound slightly after depression. The hinge region  62  can be configured to provide maximum deflection of the leaflet  52  without fracture of the hinge region  62  for a given diaphragm plate  10  material. 
       FIG. 6  is a plan view diagram of a second embodiment of a partially-etched port trace formed on a diaphragm plate  10 . By way of illustrative example, the partial-etching in this embodiment includes a curved port boundary having four port boundary partial-etches  60  partially etched thereon into the diaphragm plate  10  material. Corresponding four non-etched port boundary hinges  62  remain at the curved port boundary or port perimeter. Two generally linear partial-etches  64  are further partially-etched, each generally linear partial-etch in this embodiment extending across the port boundary and connecting two port boundary partial-etches. 
     It should be appreciated that the above partial-etching yields a quartet of partially-etched areas  52 . An individual leaflet  52  can be pie-, V- or wedge-shaped, and either of the leaflet  52  or the port trace can be considered a partially-etched predetermined portion. 
       FIGS. 7 and 8  are plan and cross-sectional side view diagrams of the open port  40  of  FIG. 6  after piercing or depression. After pressure was applied to the port area  50  from a side of the diaphragm  10 , the diaphragm plate  10  material fractured along the port boundary partial-etches  60  and generally linear partial-etch  64 . The port  40  was opened thereby and leaflets  52  were formed by the depressed or pierced portions of the diaphragm plate  10 . The depressed leaflets  52  reside out of the plane of the diaphragm plate  10 . For an embodiment wherein the diaphragm plate  10  is attached to a printhead body  30  having a fluidic chamber  42  therein, it will be appreciated that the leaflets  52  may be deflected into the body and toward the chamber  42 . 
     The number of port boundary partial-etches  60  in the second embodiment need not be limited to four. In other embodiments, partially-etched arcs and an alternating non-etched arcs can be disposed on the diaphragm plate  10 . Generally linear partial-etches  64  would be partially-etched, each generally linear partial-etch  64  disposed within the port area  50  and connecting to at least one partially-etched arc  60  on the port boundary. 
     By way of further illustrative example, an embodiment (not shown) similar to the embodiment of  FIG. 6  may be formed having three partially-etched arcs and three radial and generally linear partial-etches, with each generally linear partial-etch extending generally from the central region of the port boundary to a partially-etched arc. It should be understood that a variety of partially-etched arc/generally linear partial-etch configurations may be employed to generate various multi-leaflet structures, and that such variations and multi-leaflet structures are within the scope of the present disclosure. 
     In a further embodiment, partial etching is performed on the reverse or second side of the diaphragm  10 . This partial etching may but is not required to mimic the etching of the first side of the diaphragm  10 . By way of example, the non-partially-etched hinge region  62  may be partially etched on a reverse side of the diaphragm  10  to facilitate hinging or to promote hinging in a specific locus or pattern. 
     An advantage of the present port trace  50  is that the port traces  50  are shaped in the partial-etching step and pierced to form an open port  40 . The present method therefore permits utilization of elliptical, crenate or other port boundary shapes as desired. 
     Similarly, it is not necessary that the partially-etched arcs be of equal length; partial-etches of different lengths may be employed, resulting in non-equal leaflets. Moreover, the generally linear partial-etch of  FIGS. 6-8  need not be generally linear, but may instead be partially-etched in an arcuate or curvilinear configuration. Such leaflet variations may be used to affect flow characteristics of ink through the open port and into the fluidic chamber. 
     The claims, as originally presented and as they may be amended, encompass variations, alternatives, modifications, improvements, equivalents, and substantial equivalents of the embodiments and teachings disclosed herein, including those that are presently unforeseen or unappreciated, and that, for example, may arise from applicants/patentees and others.