Slingshot Printing LLC v. HP Inc.

Western District of Texas, txwd-6:2019-cv-00362

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USOO681 7707B1 (12) United States Patent (10) Patent No.: US 6,817,707 B1 Fowler et al. (45) Date of Patent: Nov. 16, 2004 (54) PRESSURE CONTROLLED INKJET 4,734,711 A 3/1988 Piatt et al. .................... 347/17 PRINTHEAD ASSEMBLY 4,860,787 A 8/1989 Grosselin ... ... 137/487.5 4,910,529 A 3/1990 Regnault ....................... 347/6 (75) Inventors: John R. Fowler, Nicholasville, KY SE 2Y- - - 2 A go inyl - - - - - - - - - - - i. OllaCCK C al. .............. S; Timothy L. Howard, xington, 5,126,755 A 6/1992 Sharpe et al. ................. 347/54 (US); Matthew J. Russell, 5,426,459 A 6/1995 Kaplinsky ................... 399/320 Stamping Ground, KY (US); Jon B. 5.434,603 A 7/1995 Hunt Whitney, Georgetown, KY (US) 5,440,333 A 8/1995 Sykora et al. 5.448.818 A 9/1995 Scheffelin et al. (73) Assignee: Lexmark International, Inc., 5,451,995 A 9/1995 Swanson et al. .............. 347/87 Lexington, KY (US) 5,464,578 A 11/1995 Salter et al. 5,515,092 A 5/1996 Swanson et al. (*) Notice: Subject to any disclaimer, the term of this 5,541,632 A 7/1996 Khodapanah et al.......... 347/87 patent is extended or adjusted under 35 (List continued on next page.) U.S.C. 154(b) by 0 days. page. Primary Examiner Stephen D. Meier (21) Appl. No.: 10/465,348 Assistant Examiner Alfred Dudding (74) Attorney, Agent, or Firm-Luedeka, Neely & Graham, (22) Filed: Jun. 18, 2003 P.C. (51) Int. Cl. ................................................. B41J 2/175 (57) ABSTRACT (52) U.S. Cl. ............... ... 347/86; 347/85; 347/87 (58) Field of Search .............................. 347/85, 86, 87, An inkjet printhead assembly for a pressure controlled ink 347/49 jet printhead. The assembly includes an ink reservoir made of a first material having a first melting point and having an (56) References Cited open top cavity defined by Sidewalls, a bottom wall and a U.S. PATENT DOCUMENTS peripheral edge. A pressure control Structure made of a polymeric material having a Second melting point lower than 2,609.570 A 9/1952 Danielson et al. the first melting point is included. The pressure control 3,940,773 A 2/1976 Mizoguchi et al. ........... 347/68 Structure has a first Surface, a Second Surface opposite the 4,303,929 A 12/1981 Blanck .............. ... 347/86 first Surface, a side Surface, and an aperture therein. A 4,336,544 A 6/1982 Donald et al. ... ... 347/54 Sealing Structure for forming a liquid tight Seal is provided 4,380,018 A 4/1983 Andoh et al. ................. 347/68 between the sidewalls of the ink reservoir and the side 4,385,025 A 5/1983 Salerno et al. Surface of the pressure control Structure. A pressure regu 4,462,428 A 7/1984 Guenther et al. ........... 137/868 lating film is attached over the aperture to the first Surface of 4,480.259 A 10/1984 Kruger et al. ...... ... 347/63 the pressure control Structure. A cover is attached to the ink 4,604,633 A 8/1986 Kimura et al. ................. 347/7 reservoir. 4,641,154 A 2/1987 Mikalsen ..................... 347/88 4,685,185 A 8/1987 Boso et al. .. ... 29/890.1 4,734,706 A 3/1988 Le et al. ....................... 347/71 21 Claims, 2 Drawing Sheets 3 US 6,817,707 B1 Page 2 U.S. PATENT DOCUMENTS 6,243,115 B1 6/2001 Baker et al. .................. 347/85 6,243,117 B1 6/2001 Brandon et al. 5,574,490 A 11/1996 Gragg et al. .................. 347/87 6,247,791 B1 6/2001 Silverbrook ................. 347/54 5,583,545 A 12/1996 Pawlowski, Jr. et al. ....... 347/7 6.250.747 B1 6/2001 Hauck 347/86 5,594.483. A 1/1997 Kaplinsky et al. ............ 347/87 24- - 2 - - -/f 4 - - - - uvvur-Y-La - - - - - - - - - - - - - - - - - - - - - - - - - 5610.643 A 3/1997 RN al 347/54 6.257,699 B1 7/2001 Tracy et al. .................. 347/40 5.640.186 A 6/1997 Swanson et al." 6.257,714 B1 7/2001 Seccombe 347/92 5,644,341. A 7/1997 Fujii et al. .................... 347/11 6,260,961 B1 7/2001 Seu et al. 347/87 5,646,666 A 7/1997 Cowger et al. ............... 347/87 6,270,204 B1 8/2001 Barrett et al. ................. 347/74 5,650,811 A 7/1997 Seccombe et al. ............ 347/85 6,273,151 B1 8/2001 Kong ......... ... 141/18 56.66141 A 9/1997 Matoba et al. .... ... 347/54 6,290,348 B1 9/2001 Becker et al. ................ 347/87 5710609 A 2/1998 Hauck et all 347/85 6,312,116 B2 11/2001 Underwood et al. .......... 347/86 5,736992 A 4/1998 Pawlowski Jr. - - - - - - - - - - - - - - - - 347/7 6,312,615 B1 11/2001 Silverbrook ... ... 216/27 5.737,001. A 4/1998 Taylor. 347/85 6,318,851 B1 11/2001 Hoen et al. ................... 347/92 5,745,137 A 4/1998 Scheffelin et al. ............ 347/85 3. R: S. et al- - - - - - - - - - - - - - - - - - - 3. 5,751,319 A 5/1998 Robertson et al. ............ 347/85 2-1-12 ojima et al. .. 5,757,401. A 5/1998 Abe et al............. ... 347/48 6,331,050 B1 12/2001 Nakata et al. .. ... 347/65 5,757,406 A 5/1998 Kaplinsky et al. ............ 347/87 6,331,054 B1 12/2001 Seu et al. ... . . 347/87 5,771,053 A 6/1998 Merrill ........................ 347/86 6,341,853 B1 1/2002 Scheffelin et al. ... 347/87 5,777,647 A 7/1998 Pawlowski, Jr. et al. ..... 347/86 6,364,471 B1 4/2002 Seccombe. ... 347/85 5,781,213 A 7/1998 Ujita et al. ................... 347/86 6,365,701 B1 4/2002 Hayashi et al................ 528/75 5812,163 A 9/1998 Wong. 347/68 6,371,605 B1 4/2002 Komplin et al. 5812.168 A 9/1998 Pawlowski, Jr. et al... 347/92 6,382,784 B2 5/2002 Pawlowski, Jr. et al. ..... 347/85 5,821,966 A 10/1998 Schell et al. .................. 347/86 6,383,436 B1 5/2002 Nishimuro et al. 5825,383 A 10/1998 Abe et all 347/54 6,390,603 B1 5/2002 Silverbrook ................. 347/54 2Y-4-2 - -- ----- ------ --- ----- 6,394,137 B1 5/2002 Kikuchi et al. 5,838,351 A 11/1998 Weber ........... 347/85 2- - -2 5,844,577. A 12/1998 Pawlowski, Jr. ............... 347/6 6,412,911 B1 7/2002 Hilton et al. ................. 347/49 2Y- - -2 6,416.165 B1 7/2002 Meyer et al. ... ... 347/49 5,847,734. A 12/1998 Pawlowski, Jr. ............. 347/86 2: ---Y/2 5.894,316 A 4/1999 Sakai et al. ....... ... 347/54 6,422,691 B2 7/2002 Kobayashi et al. ... 347/86 2Y- - -2 6,428,140 B1 8/2002 Cruz-Uribe ....... ... 347/20 5,912,688 A 6/1999 Gragg et al. .................. 347/86 2: 1-12 5,923,353 A 7/1999 Boyd et al. ................... 347/85 6,428,141 B1 8/2002 McElfresh et al. . . 347/40 5.975,686 A 11/1999 Hauck et all 347/85 6,428,147 B2 8/2002 Silverbrook ... ... 347/54 5,980.02s. A 1/1999 secoombe. . . 347/85 6,460,778 B1 10/2002 Silverbrook 239/102.1 5.984.463 A 11/1999 KOZmiski et a 6,478,406 B1 11/2002 Silverbrook ... 347/54 2- Y - 2 6,500,354 B1 12/2002 Lee et al. .... ... 216/27 5.992,986 A 11/1999 Gyotoku et al. .............. 347/85 2- Y-Y-2 6,000,785 A 12/1999 Sakai et al. ....... ... 347/54 6,508.545 B2 1/2003 Dowell et al. ... 347/85 6.003,984. A 12/1999 Bohorquez etal 6,527,357 B2 3/2003 Sharma et al. . . 347/17 2Y- - -2 C 6,536,875 B1 3/2003 Pan ... ... 347/54 6,007,190 A 12/1999 Murray et al. ................ 347/86 2- - - 2 6.010211 A 1/2000 Betschon .... 347/86 2001/0006395 A1 7/2001 Pawlowski, Jr. et al. ..... 347/85 6,053,607 A 4/2000 Kaplinsky etal 2001/OO13886 A1 8/2001 Underwood et al. .......... 347/86 6,074.043 A 6/2000 plinsky et al. 347/54 2001/0017641 A1 8/2001 Kobayashi et al. ... 347/85 6079,813 A 6/2000 347/54 2001/0019347 A1 9/2001 Hauck .............. ... 347/86 6,084617 A 7/2000 347/86 2001/0030675 A1 10/2001 Kobayashi et al. ... 347/86 6106.180 A 82000 401/145 2001/004O612 A1 11/2001 Shimizu ... ... 347/86 6.130,690 A 10/2000 Ahn ... 34754 2002/OOO8744 A1 1/2002 Otis et al. . ... 347/85 6.130,694. A 10/2000 Beatty. ... 347s5 2002/0O24573 A1 2/2002 Hoen et al. . . 347/92 6.164744. A 12/2000 Froger et al. ... 347 2002/003.6680 A1 3/2002 Hall et al. ... . . 347/85 6.168.267 B1 1/2001 Komplin 347/86 2002/0039124 A1 4/2002 Nanjo et al. . . . 347/49 6,172,605 B1 1/2001 Liu. ... 347ss 2002/0054194 A1 5/2002 Seccombe ... . . 347/86 2 - as ... . . . . . . . 2002/0080216 A1 6/2002 Dowell et al. ... ... 347/85 6,183,071 B1 2/2001 Sugimoto et al. ............. 347/85 6,199,977 B1 3/2001 Komplin et al. 2002/0105567 A1 8/2002 Yamada et al. ... 347/87 2- - - 2 2002/0145650 A1 10/2002 Pan et al. ..................... 347/85 6,203,146 B1 3/2001 Pawlowksi, Jr. et al. ..... 347/85 2002/0186284 A1 12/2002 Anima et al. .................. 347/85 6,206,515 B1 3/2001 Swanson et al. ...... ... 347/87 6,217,153 B1 4/2001 Silverbrook ... ... 347/54 2002/0191061 A1 12/2002 Dowell et al. ... ... 347/94 24- a 2 6,217,157 B1 4/2001 Yoshihira et al. ... 347/65 2003/0016279 A1 1/2003 Hayashi et al. ............... 347/87 6,227,654 B1 5/2001 Silverbrook ................. 347/54 2003/0052944 A1 3/2003 Scheffelin et al. ............ 347/49 6.228,050 B1 5/2001 Olsen et al. ............. 604/93.01 6,231,173 B1 5/2001 Pawlowski, Jr. et al. * cited by examiner U.S. Patent Nov. 16, 2004 Sheet 1 of 2 US 6,817,707 B1 U.S. Patent Nov. 16, 2004 Sheet 2 of 2 US 6,817,707 B1 *N, S2 54 NLH SO — • | — | ºo|?365 o0 º US 6,817,707 B1 1 2 PRESSURE CONTROLLED INKJET SUMMARY OF THE INVENTION PRINTHEAD ASSEMBLY With regard to the foregoing and other objects and advantages, the invention provides an ink jet printhead FIELD OF THE INVENTION assembly for a pressure controlled inkjet printhead. The assembly includes an ink reservoir having an open top cavity The invention relates to pressure controlled inkjet print defined by Sidewalls, a bottom wall and a peripheral edge. heads and in particular to improved printhead assemblies The ink reservoir is made of a first material having a first and to improved methods for assembling inkjet printheads. melting point. A pressure control Structure having a first BACKGROUND Surface, a Second Surface opposite the first Surface, a side Surface, and an aperture extending therethrough from the Inkjet technology continues to be improved in order to first Surface to the Second Surface is also provided. The increase printing Speed and print quality or resolution. One preSSure control Structure is made of a polymeric material means for improving print Speed and quality is to increase having a Second melting point lower than the first melting the number of nozzle holes in an inkjet printhead and to point. A Sealing Structure is provided for forming a liquid decrease the diameter of the nozzle holes. However, 15 tight seal between the sidewalls of the ink reservoir and the improvements in print Speed and quality often result in Side Surface of the preSSure control Structure. A preSSure operational problems not experienced with lower quality regulating film is attached to the first Surface of the preSSure slower Speed printers. control Structure closing the aperture therein. A cover is In an inkjet printer, ink is provided to the printhead from attached to the ink reservoir to protect the pressure regulat an ink cartridge or Supply tank. The ink flows from the tank ing film from damage. through a connecting conduit from the ink cartridge through In another embodiment, the invention provides method an ink via in a Semiconductor chip or around the edges of a for assembling a pressure controlled inkjet printhead assem Semiconductor chip and into ink flow channels and an ink bly. The method includes providing an ink reservoir having chamber. The ink chamber is situated in axial alignment with an open top cavity defined by Sidewalls, a bottom wall and a corresponding nozzle hole and a heater resistor defined on 25 a peripheral edge. The ink reservoir is made of a first the Surface of the Semiconductor chip. AS electrical impulse material having a first melting point. A pressure control energy is applied to an ink ejector adjacent an ink chamber Structure having a first Surface, a Second Surface opposite the to cause ink adjacent the ejector in the chamber to be forced first Surface, a Side Surface, and an aperture extending through a nozzle hole onto a print medium. By Selective therethrough from the first Surface to the Second Surface is activation of a plurality of ink ejectors on a printhead, a also included. The pressure control Structure is made of a pattern of ink dots are applied to the print medium to form polymeric material having a Second melting point lower than an image. the first melting point. A sealing structure is applied to the A critical aspect of the printing proceSS is the controlled Side walls of the pressure control Structure for forming a Supply of ink to the ink ejectors from the ink Supply. If the liquid tight seal between the sidewalls of the ink reservoir preSSure of the ink Supply is too high, ink may run out freely 35 and the Side Surface of the pressure control Structure. The from the nozzle holes onto the print medium before the ink preSSure control Structure is inserted in the open top cavity ejector is activated. If the pressure of the ink Supply is too of the ink reservoir. A pressure regulating film is attached to low, ink channels and chambers in the printhead will not the first Surface of the preSSure control Structure thereby refill fast enough. If the ink chambers and channels are not closing the aperture therein. A cover is attached to the ink refilled fast enough there will be missing ink dots or the print 40 reservoir to protect the pressure regulating film from dam speed must be lowered to allow time for ink to refill the ink age. chambers. Furthermore, as ink is used from the ink Supply, The invention provides a number of advantages over the preSSure of the ink Supply may decrease to a point which conventional inkjet printhead assemblies. For one, compo inhibits flow of the remaining ink to the ink ejectors. nents of the assembly may be sub assembled and combined Accordingly, as the number of nozzles holes on a printhead 45 using only mechanical means. Also, there is no need for use increases and the diameter of the holes decreases, maintain of a two step injection molding process to provide inner and ing a predetermined ink Supply pressure in the ink Supply outer frames made of different materials. Another advantage System becomes more critical. of the invention is that the components may be assembled There are two primary methods for maintaining ink with a high degree of assurance of Substantially no ink supply flow to printheads. The first method includes the use 50 leakage from the assembled components. Also, a preSSure of a porous capillary member Such as foam which is Satu control film may be made of a Single material rather than rated with ink and provides a controlled flow of ink to the from a laminate construction of two or more different printheads. The Second method includes the use of a dia materials thereby improving the pressure control response of phragm or bellows to provide preSSure or back pressure on the assembly. the ink in the cartridge. Use of a diaphragm or bellows 55 BRIEF DESCRIPTION OF THE DRAWINGS enables an ink Supply reservoir to be filled with liquid ink as opposed to the use of foam Saturated with ink. Accordingly, The above and other aspects and advantages of the the inkjet printhead assembly may be made Smaller for the invention will become further apparent by reference to the Same Volume of ink ejected onto the print media during the following detailed description of preferred embodiments life of the printhead. One disadvantage of Smaller inkjet 60 when considered in conjunction with the accompanying printhead assemblies which use a diaphragm or bellows for drawings in which: preSSure control is that manufacturing techniques become FIG. 1 is an exploded, perspective view, not to Scale, of more complicated because of a greater number of different a printhead assembly according to the invention; materials required for use in the printhead assembly. FIG. 2 is a cross-sectional view, not to Scale, of a portion There is a need therefore for an improved pressure con 65 of a printhead assembly according to the invention; and trolled ink Supply assembly and improved methods for FIG. 3 is a bottom plan view, not to scale, of a printhead assembling pressure controlled inkjet printheads. assembly according to the invention. US 6,817,707 B1 3 4 DETAILED DESCRIPTION OF THE dimensioned to accept an O-ring or bead of adhesive as the PREFERRED EMBODIMENTS Sealing structure 36. Because the Sealing Structure 36 pro With reference to FIG. I there is provided an exploded vides a liquid tight and air tight Seal between the Side Surface view in perspective of an inkjet printhead assembly 10 32 and the inner Surface 38 of side walls 16, each of the according to a preferred embodiment of the invention. The major components 12 and 26 may be separated formed or assembly 10 includes a Substantially rectangular-shaped ink molded from different materials. Also, tolerances between reservoir 12 having an open top cavity 14 defined by Side the inner Surface 38 of side walls 16 and the side Surface 32 walls 16 surrounding the cavity 14. A bottom wall 18 is of the pressure control Structure 26 are leSS critical because connected to a first end 20 of the side walls 16. A second end the Sealing Structure 36 is capable of Spanning any gap 42 22 of the Side walls 16 contains a peripheral edge 24. between the two. In order to improve assembly between the The ink reservoir 12 component of the assembly is preSSure control Structure 26 and the ink reservoir 12, Stops preferably made of a first material having a first melting 44 or a ledge may be provided to limit the distance the point. The first material may include metals, plastics, glass, preSSure control Structure can be moved into the cavity 14. ceramics, and composites of two or more of the foregoing. A preSSure regulating film 46 is preferably attached to the 15 first surface 28 of the pressure control structure 26 to close More preferably the ink reservoir 12 is molded from a material Selected from the group consisting of thermoplastic or otherwise cover the aperture 34 in the preSSure control materials including but not limited to polyphenylene oxide/ Structure 26. The pressure regulating film 46 may be made polystyrene alloys, polypropylene, acrylonitrile/butadiene/ from a wide variety of materials including, but not limited Styrene terpolymers, polystyrene/butadiene alloys or to, films that are compatible with the inks used in the ink copolymers, polyetherimide, poly Sulfone, polyesters and the printhead assembly 10 and films adaptable to welding or like, having a melting point or Softening point above about adhesive attachment thereof to the first Surface 28 of the 150° C. A particularly preferred material for ink reservoir 12 preSSure control Structure 26. Such films include polyethye is a polyphenylene ether/polystyrene resin from GE Plastics lene films and polypropylene films having a thickness rang of Pittsfield, Mass. under the trade name NORYL SE1701. ing from about 1.5 to about 3 mils. 25 An important component of the printhead assembly is a A particularly preferred film 46 is for controlling preSSure preSSure control Structure 26. The pressure control Structure in the assembly 10 is a copolymer polypropylene material 26 has a first surface 28 and a second surface 30 opposite the available from Triangle Plastics of Raleigh, N.C. under the first Surface and a side Surface 32 around the periphery trade name CPP40. The copolymer polypropylene material thereof. An aperture 34 extends through the pressure control may be laminated with an adhesive available from Minne structure 26 from the first Surface 28 to the second Surface Sota Mining and Manufacturing Company of Minneapolis, 30. Minn. under the trade name 3M-845. It is preferred however, Unlike the ink reservoir 12, the pressure control Structure to use a non-laminated film 46 that is capable of being heat 26 is preferably made of a polymeric material, preferably a welded to the first surface 28 of the pressure control struc thermoplastic material having a Second melting point lower 35 ture 26. Heat welding of the film 46 to the surface 28 may than the first melting point. Suitable materials for the pres be accomplished by providing a pressure control Structure Sure control Structure 26 include materials Selected from 26 made from a polymeric material having a similar melting polypropylene and polyethylene materials. The most pre point to that of the film 46 or having a lower melting point ferred material is polyethylene material having a melting than the melting point of the film 46. In a particularly point of about 120° C. 40 preferred embodiment, the film 46 is preferably selected AS will be described in more detail below, a flexible film from a material having Substantially the same melting point is preferably melt attached to the pressure control Structure as that of the material of the pressure control Structure 26. 26. Accordingly, making the preSSure control Structure 26 A cover 48 is preferably attached to the ink reservoir 12 from a material that enables melt attachment of a film thereto to protect the film 46 from damage and to provide additional improves the manufacturing proceSS for the assembly 10. It 45 Sealing between the ink reservoir 12 and the pressure control is also important that the ink reservoir 12 be made of a structure 26. The cover 48 may be heat welded, adhesively higher melting material than the pressure control Structure attached or Snap fit to the ink reservoir 12. In a preferred 26. Such a higher melting material is leSS Susceptible to embodiment, the cover 48 is adhesively attached to the warping and deformation due to high printhead temperatures peripheral edge of the ink reservoir 12. during printing operations. 50 A bottom wall 18 of the ink reservoir 12 preferably A sealing structure 36 is provided on side surface 32 for includes a pocket or recessed area 50 for attaching a nozzle forming a liquid tight and air tight Seal between the inner plate 52 and semiconductor chip 54 thereto (FIGS. 2 and 3). Surface 38 of side walls 16 and the side Surface 32 of the The nozzle plate 54 preferably includes a plurality of nozzle preSSure control Structure 26. The Sealing Structure 36 pref holes 56 for ejection of ink therethrough toward a print erably provides a liquid tight and air tight Seal by purely 55 media. The nozzle holes 56 may be provide in one or more mechanical means. Accordingly the Sealing Structure 36 may arrays 58 along the length of the nozzle plate 52. An ink feed be selected from elastomeric materials and adhesives. A via 60 in the chip 54 provides a flow of ink to ink ejectors particularly preferred Sealing Structure 36 is an elastomeric on the chip 54. The ink ejectors may be selected from O-ring made from ethylene propylene diene monomer thermal or electromechanical type ejectors including heater (EPDM). Regardless of whether the sealing structure 36 is 60 resistors and piezoelectric devices. an adhesive or elastomeric O-ring material, it is preferred Because the pressure regulating Structure 26 and ink that the sealing structure 36 be substantially chemically reservoir 12 components of the assembly 10 may be made resistant to the components of ink used in the printhead Separately from different materials, assembly of the compo assembly 10. nents to provide the printhead assembly 10 can be achieved As shown in more detail in FIG. 2, the pressure control 65 in a variety of ways. For example, the film 46 may be structure 26 preferably includes a peripheral groove 40 in attached to the first surface 28 of the pressure control the side surface 32 thereof. The groove 40 is preferably Structure 26 prior to inserting the pressure control Structure US 6,817,707 B1 S 6 26 into the cavity 14 of the ink reservoir 12. In the 2. The inkjet printhead assembly of claim 1 wherein the alternative, the pressure regulating Structure 26 may be Side Surface of the pressure control Structure further com inserted into the cavity 14 of the ink reservoir 12 before prises a peripheral groove. attaching the film 46 to the first surface 28 of the pressure 3. The inkjet printhead assembly of claim 2 wherein the control structure 26. Either method will provide an Sealing Structure comprising an elastomeric O-ring disposed improved pressure controlled inkjet printhead assembly 10 in the peripheral groove. according to the invention. 4. The inkjet printhead assembly of claim 2 wherein the Ink is preferably inserted into cavity 14 before attaching Sealing Structure comprises a bead of adhesive disposed in the film 46 to the pressure control structure 26 when the the peripheral groove. preSSure control Structure 26 is first inserted into cavity 14. 5. The inkjet printhead assembly of claim 1 wherein the If the film is first attached to the pressure control structure Sealing Structure comprising an elastomeric o-ring. 26 before the preSSure control Structure is inserted into 6. The ink jet printhead assembly of claim 1 further cavity 14, then the ink is inserted into the cavity 14 before comprising a Semiconductor Substrate and nozzle plate inserting the pressure control Structure 26 into cavity 14. attached to the bottom wall of the ink reservoir. After the cavity 14 is filled with ink, and the cover 48 is 15 7. The inkjet printhead assembly of claim 1 wherein the attached to the ink reservoir 12, a reduced pressure or back preSSure regulating film is melt attached to the first Surface preSSure is applied to the cavity 14, preferably through an opening in the ink reservoir 12, to provide a predetermined of the pressure control Structure. pressure differential between cavity 14 and the nozzle plate/ 8. A method for assembling a pressure controlled inkjet chip assembly 52/54. As ink is ejected through the nozzle printhead assembly comprising: holes 56, the volume of ink in cavity 14 decreases. The providing an ink reservoir having an open top cavity pressure regulator structure 26 and film 46 are effective to defined by Sidewalls, a bottom wall and a peripheral maintain a predetermined preSSure in cavity 14 as the edge, the ink reservoir being made of a first material Volume of ink in the cavity decreases. The pressure regulator having a first melting point; and a preSSure control structure 26 and film 46 also helps to compensate for Structure having a first Surface, a Second Surface oppo preSSure changes in ink cavity 14 due to ambient tempera 25 Site the first Surface, a Side Surface, and an aperture ture and pressure changes. In most instances, the predeter extending therethrough from the first Surface to the mined minimum pressure or back preSSure maintained in the Second Surface, the preSSure control Structure being cavity 14 ranges from about -8 to about -24 centimeters made of a polymeric material having a Second melting (cm) of water. point lower than the first melting point, In a particularly preferred embodiment, a biasing device applying a Sealing Structure to the Side walls of the Such as a coil spring, leaf Spring, resilient foam or the like preSSure control Structure for forming a liquid tight Seal is included in the pressure cavity 14 to bias the film 46 away between the sidewalls of the ink reservoir and the side from the bottom wall 18 of the ink reservoir 12 in order to Surface of the pressure control Structure; maintain a predetermined pressure on ink in the reservoir 12. 35 inserting the pressure control Structure in the open top In an alternative embodiment, the biasing device may be cavity of the ink reservoir; disposed between the cover 48 and the film 46 to bias the attaching a pressure regulating film to the first Surface of film 46 toward the bottom wall 18 of the ink reservoir 12 in the pressure control Structure thereby closing the aper order to maintain a predetermined pressure in the reservoir ture therein; and 12. The foregoing description of certain exemplary embodi 40 attaching a cover to the ink reservoir to protect the preSSure regulating film from damage. ments of the present invention has been provided for pur 9. The method of claim 8 wherein the side Surface of the poses of illustration only, and it is understood that numerous preSSure control Structure further comprises a peripheral modifications, alterations, Substitutions, or changes may be grOOVe. made in and to the illustrated embodiments without depart 45 10. The method of claim 9 wherein the sealing structure ing from the Spirit and Scope of the invention. comprising an elastomeric O-ring, and wherein the Step of What is claimed is: applying the Sealing Structure comprises disposing the O-ring 1. An inkjet printhead assembly for a pressure controlled in the peripheral groove. inkjet printhead comprising: 11. The method of claim 9 wherein the sealing structure an ink reservoir having an open top cavity defined by 50 comprises a bead of adhesive and wherein the Step of Sidewalls, a bottom wall and a peripheral edge, the ink applying the Sealing structure comprises disposing the adhe reservoir being made of a first material having a first Sive in the peripheral groove. melting point; 12. The method of claim 8 wherein the sealing structure a pressure control Structure having a first Surface, a Second comprising an elastomeric O-ring. Surface opposite the first Surface, a Side Surface, and an 55 13. The method of claim 8 further comprising attaching a aperture extending therethrough from the first Surface Semiconductor Substrate and nozzle plate to the bottom wall to the Second Surface, the preSSure control Structure of the ink reservoir. being made of a polymeric material having a Second 14. The method of claim 8 wherein the step of attaching melting point lower than the first melting point; the pressure regulating film comprises melt attaching the a Sealing Structure for forming a liquid tight Seal between 60 film to the first Surface of the preSSure control Structure. the sidewalls of the ink reservoir and the side Surface of 15. A method for assembling a pressure controlled inkjet the pressure control Structure; printhead assembly comprising: a preSSure regulating film attached to the first Surface of providing an ink reservoir having an open top cavity the pressure control Structure closing the aperture defined by Sidewalls, a bottom wall and a peripheral therein; and 65 edge, the ink reservoir being made of a first material a cover attached to the ink reservoir to protect the pressure having a first melting point; and a preSSure control regulating film from damage. Structure having a first Surface, a Second Surface oppo US 6,817,707 B1 7 8 Site the first Surface, a Side Surface, and an aperture 17. The method of claim 16 wherein the sealing structure extending therethrough from the first Surface to the comprising an elastomeric O-ring, and wherein the Step of Second Surface, the pressure control Structure being applying the Sealing Structure comprises disposing the O-ring made of a polymeric material having a Second melting in the peripheral groove. point lower than the first melting point, 18. The method of claim 16 wherein the sealing structure applying a Sealing Structure to the Side walls of the comprises a bead of adhesive and wherein the Step of preSSure control Structure for forming a liquid tight Seal applying the Sealing structure comprises disposing the adhe between the sidewalls of the ink reservoir and the side Surface of the pressure control Structure; Sive in the peripheral groove. attaching a pressure regulating film to the first Surface of 19. The method of claim 15 wherein the sealing structure the pressure control Structure thereby closing the aper comprising an elastomeric O-ring. ture therein; 20. The method of claim 15 further comprising attaching inserting the pressure control Structure in the open top a Semiconductor Substrate and nozzle plate to the bottom of cavity of the ink reservoir; and the ink reservoir. 15 attaching a cover to the ink reservoir to protect the 21. the method of claim 15 wherein the step of attaching preSSure regulating film from damage. the pressure regulating film comprises melt attaching the 16. The method of claim 15 wherein the side Surface of film to the first Surface of the preSSure control Structure. the pressure control Structure further comprises a peripheral grOOVe.