Fluidic adapter for use with an inkjet print cartridge having an internal pressure regulator

Described is an ink delivery system for an inkjet printing system including a housing; a printhead fixed to the housing for ejecting droplets of ink on media; a regulator located within the housing; a source of ink for replenishing the printhead; and an ink passageway for connecting the source of ink and the valve inlet. The regulator including a valve having an inlet and outlet, with the outlet in fluid communication with the printhead; a flexible member within the print cartridge, the flexible member has a reference surface and an ink surface, the reference surface is in communication with an outside atmosphere, the ink surface is in fluid communication with the printhead, the difference in pressure between the outside atmosphere and the printhead causes the flexible member to bias toward the ink surface; and an actuator that is receives a force from the ink surface of the flexible member, the actuator actuates the valve based upon the differential pressure between the reference surface and the outside atmosphere. Also described is a fluidic coupling that releasably and fluidically connects to the inlet port of a print cartridge. The fluidic coupling acts as a seal for the print cartridge and a means of lubricating and protecting the inlet port from drying, leaking ink, and air ingestion while the print cartridge is in transit and in storage. The fluidic coupling also provides an auxiliary ink reservoir for the print cartridge. The fluidic coupling further provides an ink conduit to the printhead from an external ink supply.

FIELD OF THE INVENTION
 This invention relates to inkjet printers and, more particularly, to an
 inkjet printer having a scanning printhead with a stationary ink supply.
 BACKGROUND OF THE INVENTION
 Thermal inkjet hardcopy devices such as printers, graphics plotters,
 facsimile machines and copiers have gained wide acceptance. These hardcopy
 devices are described by W. J. Lloyd and H. T. Taub in "Ink Jet Devices,"
 Chapter 13 of Output Hardcopy Devices (Ed. R. C. Durbeck and S. Sherr, San
 Diego: Academic Press, 1988) and U.S. Pat. Nos. 4,490,728 and 4,313,684.
 The basics of this technology are further disclosed in various articles in
 several editions of the Hewlett-Packard Journal [Vol. 36, No. 5 (May
 1985), Vol. 39, No. 4 (August 1988), Vol. 39, No. 5 (October 1988), Vol.
 43, No. 4 (August 1992), Vol. 43, No. 6 (December 1992) and Vol. 45, No.1
 (February 1994)], incorporated herein by reference. Inkjet hardcopy
 devices produce high quality print, are compact and portable, and print
 quickly and quietly because only ink strikes the paper.
 An inkjet printer forms a printed image by printing a pattern of individual
 dots at particular locations of an array defined for the printing medium.
 The locations are conveniently visualized as being small dots in a
 rectilinear array. The locations are sometimes "dot locations", "dot
 positions", or pixels". Thus, the printing operation can be viewed as the
 filling of a pattern of dot locations with dots of ink.
 Inkjet hardcopy devices print dots by ejecting very small drops of ink onto
 the print medium and typically include a movable carriage that supports
 one or more printheads each having ink ejecting nozzles. The carriage
 traverses over the surface of the print medium, and the nozzles are
 controlled to eject drops of ink at appropriate times pursuant to command
 of a microcomputer or other controller, wherein the timing of the
 application of the ink drops is intended to correspond to the pattern of
 pixels of the image being printed.
 The typical inkjet printhead (i.e., the silicon substrate, structures built
 on the substrate, and connections to the substrate) uses liquid ink (i.e.,
 dissolved colorants or pigments dispersed in a solvent). It has an array
 of precisely formed orifices or nozzles attached to a printhead substrate
 that incorporates an array of ink ejection chambers which receive liquid
 ink from the ink reservoir. Each chamber is located opposite the nozzle so
 ink can collect between it and the nozzle. The ejection of ink droplets is
 typically under the control of a microprocessor, the signals of which are
 conveyed by electrical traces to the resistor elements. When electric
 printing pulses heat the inkjet firing chamber resistor, a small portion
 of the ink next to it vaporizes and ejects a drop of ink from the
 printhead. Properly arranged nozzles form a dot matrix pattern. Properly
 sequencing the operation of each nozzle causes characters or images to be
 printed upon the paper as the printhead moves past the paper.
 The ink cartridge containing the nozzles is moved repeatedly across the
 width of the medium to be printed upon. At each of a designated number of
 increments of this movement across the medium, each of the nozzles is
 caused either to eject ink or to refrain from ejecting ink according to
 the program output of the controlling microprocessor. Each completed
 movement across the medium can print a swath approximately as wide as the
 number of nozzles arranged in a column of the ink cartridge multiplied
 times the distance between nozzle centers. After each such completed
 movement or swath the medium is moved forward the width of the swath, and
 the ink cartridge begins the next swath. By proper selection and timing of
 the signals, the desired print is obtained on the medium.
 Color inkjet hardcopy devices commonly employ a plurality of print
 cartridges, usually either two or four, mounted in the printer carriage to
 produce a full spectrum of colors. In a printer with four cartridges, each
 print cartridge contains a different color ink, with the commonly used
 base colors being cyan, magenta, yellow, and black. In a printer with two
 cartridges, one cartridge usually contains black ink with the other
 cartridge being a tri-compartment cartridge containing the base color
 cyan, magenta and yellow inks. The base colors are produced on the media
 by depositing a drop of the required color onto a dot location, while
 secondary or shaded colors are formed by depositing multiple drops of
 different base color inks onto the same dot location, with the
 overprinting of two or more base colors producing the secondary colors
 according to well established optical principles.
 For many applications, such as personal computer printers and fax machines,
 the ink reservoir has been incorporated into the pen body such that when
 the pen runs out of ink, the entire pen, including the printhead, is
 replaced.
 However, for other hardcopy applications, such as large format plotting of
 engineering drawings, color posters and the like, there is a requirement
 for the use of much larger volumes of ink than can be contained within the
 replaceable pens. Therefore, various off-board ink reservoir systems have
 been developed recently which provide an external stationary ink supply
 connected to the scanning cartridge via a tube. The external ink supply is
 typically known as an "off-axis," "off-board," or "off-carriage" ink
 supply. While providing increased ink capacity, these off-carriage systems
 also present a number of problems. The space requirements for the
 off-carriage reservoirs and tubing impact the size of the printer, with
 consequent cost increase.
 These various problems include undesirable fluctuations in ink pressure in
 the print cartridge, an unreliable and complex fluid seal between the
 print cartridge and the external ink supply, increased printer size due to
 the external ink supply's connection to the print cartridge, blockage in
 the ink delivery system, air accumulation in the tubes leading to the
 print cartridge, leakage of ink, high cost, and complexity.
 More importantly, the new off-axis design print cartridges have very little
 internal ink capacity in their reservoirs. Each time a new cartridge is
 manufactured, it needs to be run through an automated print quality tester
 (APQT). This allows the manufacturer to screen out cartridges failing to
 meet minimum quality standards. This testing requires the use of ink.
 Additional production line processes that use ink may include a nozzle
 down flush, wetfiring, and reprinting. With the new off-axis cartridge
 designs, the amount of ink available internally may not be enough to make
 it through the APQT test and other uses of ink.
 Prior to printer installation, the cartridge is in transit and in storage.
 Therefore, there is also a need to provide a means of lubricating and
 protecting the inlet port. In particular, the port should be protected
 from drying, leaking ink, and air ingestion.
 What is needed is an fluidic coupling that releasably and fluidically
 connects to the inlet port of a print cartridge for ink replenishment so
 as to provide a print cartridge seal from the outside atmosphere,
 compliance, and an auxiliary ink source for the print cartridge.
 SUMMARY
 The present invention provides fluidic coupling that releasably and
 fluidically connects to the inlet port of a print cartridge. The fluidic
 coupling acts as a seal for the print cartridge and a means of lubricating
 and protecting the inlet port from drying, leaking ink, and air ingestion
 while the print cartridge is in transit and in storage. The fluidic
 coupling also provides an auxiliary ink reservoir for the print cartridge.
 The fluidic coupling further provides an ink conduit to the printhead from
 an external ink supply. The fluidic adapter of the present invention is
 advantageously utilized in an inkjet printer which includes a replaceable
 print cartridge which is inserted into a scanning carriage. A fluid
 interconnect on the print cartridge connects to a fluid interconnect on
 the carriage when the print cartridge is inserted into the carriage to
 complete the fluid connection between the external ink supply and the
 print cartridge. The fluid interconnection is made between the print
 cartridge and the ink tube simply by placing the print cartridge into a
 stall in the scanning carriage. A pressure regulator, which may be
 internal or external to the print cartridge, regulates the flow of ink
 from the external ink supply to the print cartridge. The external ink
 supply may be pressurized or non-pressurized.
 The present invention is an ink delivery system for an inkjet printing
 system including a housing; a printhead fixed to the housing for ejecting
 droplets of ink on media; a regulator located within the housing; a source
 of ink for replenishing the printhead; and an ink passageway for
 connecting the source of ink and the valve inlet. The regulator including
 a valve having an inlet and outlet, with the outlet in fluid communication
 with the printhead; a flexible member within the print cartridge, the
 flexible member has a reference surface and an ink surface, the reference
 surface is in communication with an outside atmosphere, the ink surface is
 in fluid communication with the printhead, the difference in pressure
 between the outside atmosphere and the printhead causes the flexible
 member to bias toward the ink surface; and an actuator that is receives a
 force from the ink surface of the flexible member, the actuator actuates
 the valve based upon the differential pressure between the reference
 surface and the outside atmosphere.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
 FIG. 1A is a perspective view of one embodiment of an inkjet printer 10,
 with its cover removed, incorporating various inventive features.
 Generally, printer 10 includes a tray 12 for holding virgin paper. When a
 printing operation is initiated, a sheet of paper from tray 12 is fed into
 printer 10 using a sheet feeder, then brought around in a U direction to
 now travel in the opposite direction toward tray 12. The sheet is stopped
 in a print zone 14, and a scanning carriage 16, containing one or more
 print cartridges 18, is then scanned across the sheet for printing a swath
 of ink thereon.
 After a single scan or multiple scans, the sheet is then incrementally
 shifted using a conventional stepper motor and feed rollers 20 to a next
 position within print zone 14, and carriage 16 again scans across the
 sheet for printing a next swath of ink. When the printing on the sheet is
 complete, the sheet is forwarded to a position above tray 12, held in that
 position to ensure the ink is dry, and then released.
 Alternative embodiment printers include those with an output tray located
 at the back of printer 10, where the sheet of paper is fed through the
 print zone 14 without being fed back in a U direction.
 The carriage 16 scanning mechanism may be conventional and generally
 includes a slide rod 22, along which carriage 16 slides, and a coded strip
 24 which is optically detected by a photodetector in carriage 16 for
 precisely positioning carriage 16. A stepper motor (not shown), connected
 to carriage 16 using a conventional drive belt and pulley arrangement, is
 used for transporting carriage 16 across print zone 14.
 The novel features of inkjet printer 10 and the other inkjet printers
 described in this specification relate to the ink delivery system for
 providing ink to the print cartridges 18 and ultimately to the ink
 ejection chambers in the printheads. This ink delivery system includes an
 off-axis ink supply station 30 containing replaceable ink supply
 cartridges 31, 32, 33, and 34, which may be pressurized or at atmospheric
 pressure. For color printers, there will typically be a separate ink
 supply cartridge for black ink, yellow ink, magenta ink, and cyan ink.
 Four tubes 36 carry ink from the four replaceable ink supply cartridges
 31-34 to the four print cartridges 18.
 Various embodiments of the off-axis ink supply, scanning carriage, and
 print cartridges will be described herein.
 FIG. 1B is a top down view of another printer 10 very similar to that shown
 in FIG. 1A, but with the paper tray removed. An electrical connector 37 is
 shown connected between printer 10 and a personal computer. Elements
 throughout the various figures identified with the same numerals may be
 identical.
 FIG. 2 illustrates the ink delivery system of an alternative embodiment
 printer 40. In this embodiment, four replaceable ink supply cartridges
 42-45 are shown installed in a fixed station 46 above a scanning carriage
 48. This particular location of station 46 and the horizontal arrangement
 of ink supply cartridges 42-45 results in an efficient utilization of
 available space within printer 40. In another embodiment, station 46 may
 be located virtually anywhere within printer 40.
 A single print cartridge 50 is shown installed in carriage 48. Four tubes
 36, each connected to an ink supply cartridge 42-45, are in fluid
 connection with a rubber septum 52 for each of the four stalls in carriage
 48. A hollow needle 60 (FIG. 3A) formed as part of each print cartridge 50
 is inserted through the rubber septum 52 upon pushing the print cartridge
 50 into its associated stall within carriage 48 so that a fluid
 communication path exists between a particular ink supply cartridge 42-45
 and a particular print cartridge 50 for providing a supply of ink to the
 print cartridge 50.
 A sheet of paper enters through the bottom portion of printer 40 in the
 direction of arrow 53, then guided back in a U direction, and transported
 through the print zone 14 in the direction of arrow 54. Carriage 48 then
 scans across print zone 14 for printing on the sheet. In another
 embodiment, a sheet of paper enters the print zone 14 in the direction of
 arrow 53.
 FIG. 3A is a perspective view looking up at carriage 48, showing print
 cartridge 50 and septum 52 in cross-section. This cross-section does not
 show a regulator valve within print cartridge 50 that regulates pressure
 by opening and closing hole 65. An opening in the bottom of carriage 48
 exposes the printhead location 58 of each print cartridge 50. Carriage
 electrodes 49 oppose contact pads located on print cartridge 50.
 When the aforementioned regulator valve is opened, a hollow needle 60 is in
 fluid communication with an ink chamber 61 internal to print cartridge 50.
 The hollow needle 60 extends through a self-sealing slit formed through
 the center of septum 52. This self-sealing slit is automatically sealed by
 the resiliency of the rubber septum 52 when needle 60 is removed.
 A plastic ink conduit 62 leads from needle 60 to ink chamber 61 via hole
 65. Conduit 62 may also be integral to the print cartridge body. Conduit
 62 may be glued, heat-staked, ultrasonically welded, or otherwise secured
 to the print cartridge body.
 Ink is provided to carriage 48 by tubes 36 which connect to a plastic
 manifold 66. Tubes 36 may be formed of Polyvinylidene Chloride (PVDC),
 such as Saran.TM., or other suitable plastic. Tubes 36 may also be formed
 of a very flexible polymer material and dipped in PVDC for reducing air
 diffusion through the tubes. In the preferred embodiment, non-pressurized
 ink tubes 36 have an internal diameter between approximately 1.5-2.5 mm,
 while pressurized ink tubes 36 have an internal diameter between
 approximately 1-1.5 mm. Manifold 66 provides several 90.degree.
 redirections of ink flow. Such a manifold 66 may not be needed if tubes 36
 are sufficiently slender and can be bent without buckling. A pressurized
 off-axis ink supply (described later) may utilize such slender tubing. An
 alternative to manifold 66 is a series of elbows molded or formed out of
 heat formed tubing.
 A septum elbow 71 routes ink from manifold 66 to septum 52 and supports
 septum 52. Septum 52 is affixed to elbow 71 using a crimp cap 73.
 A bellows 67 (shown in cross-section) is provided for each of the
 individual stalls 68 for allowing a degree of x, y, and z movement of
 septum 52 when needle 60 is inserted into septum 52 to minimize the x, y,
 and z load on needle 60 and ensure a fluid-tight and air-tight seal around
 needle 60. Bellows 67 may be formed of butyl rubber, high acn nitrile, or
 other flexible material with low vapor and air transmission properties.
 Bellow 67 can be any length and can even be a flexible diaphram.
 A spring 70 urges septum 52 upward. This allows septum 52 to take up z
 tolerances, minimizes the load on needle 60, and ensures a tight seal
 around needle 60.
 Slots 72 formed on each of the stalls 68 in carriage 48 align with tabs on
 each print cartridge 50 to restrict movement of the print cartridge 50
 within the stall 68.
 An air vent 74 formed in the top of print cartridge 50 is used by a
 pressure regulator in print cartridge 50, to be described later. In an
 alternative embodiment, a separate regulator may be connected between the
 off-axis ink supply and each print cartridge 50.
 FIG. 3B is a perspective view of carriage 48 looking down on carriage 48
 and showing one print cartridge 50 installed.
 In other embodiments, shown in FIGS. 3C-3F, bellows 67 is replaced with a
 U-shaped, circular, or straight flexible tube.
 FIG. 3C illustrates a circular flexible tube 63 connected between elbow 71
 and manifold 66.
 FIG. 3D is a top down view of the carriage 16 incorporating tube 63.
 In another embodiment, shown in FIG. 3E, manifold 66 is deleted, and tubes
 63 are connected to (or are part of) tube 36. A plastic guide 64 may be
 used to guide the tubes 63.
 In FIG. 3F, the tubes 36 are directly connected to the rigid plastic elbow
 71 supporting septum 52 without being coiled.
 If desired, the print cartridges can be secured within the scanning
 carriage by individual latches, which may be manually operated or spring
 loaded, where the latches press down on a tab or a corner of the print
 cartridge. In another embodiment, a single latch, such as a hinged bar,
 secures all four print cartridges in place within the carriage.
 FIG. 4 is a detailed view of manifold 66, tubes 36, crimp cap 73, septum
 52, septum elbow 71, spring 70, and bellows 67 described with respect to
 FIG. 3A. A stress reliever 77 for tubes 36 is also shown.
 FIG. 5A is a perspective view of one embodiment of print cartridge 50. A
 shroud 76 (also shown in FIG. 3B) surrounds needle 60 (obscured by shroud
 76) to prevent inadvertent contact with needle 60 and also to help align
 septum 52 (FIG. 3A) with needle 60 when installing print cartridge 50 in
 carriage 48.
 Coded tabs 79 align with coded slots in the carriage stalls 68 to ensure
 the proper color print cartridge 50 is placed in the proper stall 68. In
 another embodiment, coded tabs 79 are located on shroud 76.
 A flexible tape 80 containing contact pads 86 leading to the printhead
 substrate is secured to print cartridge 50. These contact pads 86 align
 with and electrically contact electrodes 49 (FIG. 3A) on carriage 48.
 Preferably, the electrodes on carriage 48 are resiliently biased toward
 print cartridge 50 to ensure a reliable contact. Such carriage electrodes
 are found in U.S. Pat. No. 5,408,746, entitled Datum Formation for
 Improved Alignment of Multiple Nozzle Members in a Printer, by Jeffrey
 Thoman et al., assigned to the present assignee and incorporated herein by
 reference.
 The printhead nozzle array is at location 58. An integrated circuit chip 78
 provides feedback to the printer regarding certain parameters of print
 cartridge 50.
 FIG. 5B illustrates the bottom side of print cartridge 50. Two parallel
 rows of offset nozzles 82 are shown laser ablated through tape 80. An ink
 fill hole 81 is used to initially fill print cartridge 50 with ink. A
 stopper (not shown) is intended to permanently seal hole 81 after the
 initial filling.
 FIG. 5C is a cross-sectional view of print cartridge 50, without tape 80,
 taken along line 5C--5C in FIG. 5A. Shroud 76 is shown having an inner
 conical or tapered portion 75 to receive septum 52 and center septum 52
 with respect to needle 60. In an alternative embodiment, needle 60 is part
 of a separate subassembly, and shroud 76 is a separate subassembly, for
 manufacturing ease and to allow color key changing by changing the shroud,
 assuming the color key tabs are located on the shroud.
 The print cartridges and ink supply connections described above are
 down-connect types where the ink connection is made when pressing the
 print cartridge down into the carriage. This enables a resulting printer
 to have a very low profile since the ink path does not extend above the
 print cartridge. In the embodiments shown having the needle extending from
 the print cartridge, the needle may be replaced with a septum, and the
 septum on the scanning carriage replaced with a hollow needle.
 FIGS. 6, 7, and 8 illustrate the basic principles of the printhead assembly
 83. Printhead assembly 83 is preferably a flexible polymer tape 80 (FIG.
 5B) having nozzles 82 formed therein by laser ablation. Conductors 84
 (FIG. 7) are formed on the back of tape 80 and terminate in contact pads
 86 for contacting electrodes on carriage 48. The other ends of conductors
 84 are bonded through windows 87 to terminals of a substrate 88 (FIG. 7)
 on which are formed the various ink ejection chambers and ink ejection
 elements. The ink ejection elements may be heater resistors or
 piezoelectric elements. The printhead assembly may be similar to that
 described in U.S. Pat. No. 5,278,584, by Brian Keefe, et al., entitled
 "Ink Delivery System for an Inkjet Printhead," assigned to the present
 assignee and incorporated herein by reference. In such a printhead
 assembly, ink within print cartridge 50 flows around the edges of the
 rectangular substrate 88 and into ink channels 90 leading to each of the
 ink ejection chambers.
 FIG. 8 illustrates the flow of ink 92 from the ink chamber 61 within print
 cartridge 50 to ink ejection chambers 94. Energization of the ink ejection
 elements 96 and 98 cause a droplet of ink 101, 102 to be ejected through
 the associated nozzles 82. A photoresist barrier layer 104 defines the ink
 channels and chambers, and an adhesive layer 106 affixes the flexible tape
 80 to barrier layer 104. Another adhesive 108 provides a seal between tape
 80 and the plastic print cartridge body 110. In one embodiment, a wall 112
 separates the ink flow paths around the two edges of substrate 88, and a
 different color ink is supplied to each side of wall 112.
 The conductor portion of the flexible tape 80 is glued or heat-staked to
 the print cartridge body 110.
 A demultiplexer on substrate 88 demultiplexes the incoming electrical
 signals applied to contact pads 86 and selectively energizes the various
 ink ejection elements to eject droplets of ink from nozzles 82 as
 printhead 79 scans across the print zone. In one embodiment, the dots per
 inch (dpi) resolution is 300 dpi, and there are 300 nozzles 82. In another
 embodiment, at least the black ink cartridge prints at a resolution of 600
 dpi.
 FIG. 9A is a perspective view of another embodiment scanning carriage 120
 having four print cartridges 122-125 installed. One of the print
 cartridges 122 is shown in FIG. 10. Tubes 36 from an off-axis ink supply
 station 128 (FIG. 9B) supply ink to a manifold 130 which redirects the ink
 to a 90.degree. interface cap 132 for each of print cartridges 122-125.
 Preferably, each cap 132 is of a color similar to the color ink within
 each print cartridge 122-125. This embodiment differs from that shown in
 FIG. 3A in that the ink is coupled to print cartridges 122-125 by pressing
 a septum 133 (FIG. 11) down onto a hollow needle 134 (FIG. 10) extending
 from the top of the print cartridge 122, rather than pressing a needle 60
 (FIG. 3A) down into the septum 52 (FIG. 3A). Also shown in FIG. 10 are air
 vent 74 for an internal pressure regulator, coded tabs 135 for ensuring
 the proper color print cartridge is installed in the proper carriage
 stall, and the location 58 of the printhead.
 In the particular embodiment shown in FIG. 9B, only three out of the four
 color ink supply cartridges 136-139 are installed in ink supply station
 128. A hollow needle 142 extending from a stall in the ink supply station
 128, to be described in greater detail with respect to FIGS. 12B and 12C,
 is in fluid communication with one of tubes 36. The ink within each of ink
 supply cartridges 136-139 is at atmospheric pressure, and ink is drawn
 into each of print cartridges 122-125 by a negative pressure within each
 print cartridge 122-125 determined by a regulator internal to each print
 cartridge.
 In another embodiment, to be described later, the off-axis ink supply
 cartridges are pressurized. In both the pressurized and unpressurized ink
 supply embodiments, the regulator internal to each print cartridge
 regulates the pressure of ink supplied to the print cartridge.
 In another embodiment, shown in FIG. 11B, the print cartridges 122
 installed in carriage 120 have ink supply cartridges 139 connected
 directly to needle 134, so that carriage 120 supports the print cartridges
 122 and the ink supply cartridges 139. A septum on the ink supply
 cartridges 139 connect to needle 134 in a manner similar to that shown in
 FIG. 11A. The ink supply cartridges 139 are preferably made to have a low
 profile to achieve a low profile printer.
 FIG. 12A is a side view of the carriage 120 and print cartridge assembly of
 FIG. 9A connected to the off-axis ink supply station 128 via tubes 36.
 FIG. 12B is a cross-sectional view of ink supply cartridge 138 in the
 off-axis ink supply station 128 taken along line 12B--12B in FIG. 9B. As
 seen, a hollow needle 142 extending in an upward direction from the ink
 supply support 144 is inserted through a rubber septum 146 on ink supply
 cartridge 138 to create a fluid communication path between the ink
 reservoir 148 within ink supply cartridge 138 and one ink conduit within
 manifold 150. In one embodiment, ink reservoir 148 comprises a collapsible
 ink bag, to be described later. The ink conduits within manifold 150 are
 coupled to tubes 36 which connect to the various print cartridges within
 scanning carriage 120.
 FIG. 12C is a detailed view of needle 142 extending from the ink supply
 station 128. Also shown are a spring-loaded humidor 145, having a rubber
 portion 145' which covers needle hole 147 when the ink supply cartridge
 138 is removed, and a plastic elbow 149 connected to tube 36. Elbows 149
 replace manifold 150 (FIG. 12B) in the embodiment of FIG. 12C.
 FIG. 13 is a perspective view of manifold 150 in the off-axis ink supply
 station 128 of FIG. 12B. Manifold 150 is opened to reveal the internal ink
 conduits 152-155.
 FIG. 14 is a perspective view of the four ink conduits 156 in manifold 130
 on the scanning carriage 120 of FIG. 9A for redirecting the flow of ink
 from tubes 36 to print cartridges 122-125 in FIG. 9A.
 FIG. 15 is perspective view of another embodiment print cartridge 158 in
 partial cross-section.
 Print cartridge 158 of FIG. 15 may be similar to any one of print
 cartridges 122-125 shown in FIG. 9A except that, instead of having a
 needle protruding from a top surface of the print cartridge, print
 cartridge 158 has a rubber septum 160 for receiving a hollow needle. Print
 cartridge 158 is to be installed in a carriage similar to carriage 120 in
 FIG. 9A. An axial passage 162 communicates between a central slit formed
 in septum 160 and an ink chamber 164 within print cartridge 158. A cap 166
 is crimped onto neck 168 and onto septum 160 to form a seal between septum
 160 and the remainder of the print cartridge 158. The crimping of cap 166
 also serves to compress septum 160 so as to ensure the central slit is
 sealed.
 The flexible tape 80 forming a part of the printhead assembly is shown
 revealed on a side of print cartridge 158. Contact pads 86 for connection
 to electrodes on a carriage are also shown.
 FIG. 16 illustrates the fluid interconnect between an ink supply tube 36
 and septum 160 of print cartridge 158. Tube 36, connected to an off-axis
 ink supply, is fitted over a hollow needle 170. Needle 170 is preferably
 18-gage stainless steel having a diameter of about 1.2 mm. A housing 172
 on the scanning carriage houses a spring 174 and a sliding humidor
 consisting of a rigid plastic collar 176 and a compliant inner portion
 178. A pocket 180 in the compliant inner portion 178 reduces the friction
 between the compliant inner portion 178 and needle 170. In FIG. 16, print
 cartridge 158 is installed in the carriage prior to the fluid interconnect
 being made.
 FIG. 17 shows the completed fluid interconnect between the off-axis ink
 supply and print cartridge 158 after the fluid interconnect system on the
 carriage has been brought down onto print cartridge 158. The downward
 force of the fluid interconnect system compresses spring 174 while causing
 needle 170 to be inserted through a central slit in septum 160. The
 compliant inner portion.178 and rubber septum 160 are in contact with one
 another. Ink now flows from the off-axis ink supply station, through tube
 36, through hollow needle 170, through hole 182 formed in hollow needle
 170, through axial passage 162, and into the print cartridge's ink chamber
 164 (FIG. 15).
 In another embodiment, needle 170 directly extends from a replaceable ink
 supply cartridge, such as from ink supply cartridge 139 in FIG. 11B, and
 the ink supply cartridge and print cartridges 158 are supported by the
 scanning carriage.
 The central slit formed in septum 160 creates an air-tight seal around
 needle 170. The slit becomes sealed when needle 170 is withdrawn from
 septum 160.
 Print cartridge 158 is thus supplied with ink from the off-axis ink supply
 station.
 Thus, a number of print cartridge embodiments and ink interconnections
 between an off-axis ink supply and the print cartridge have been shown.
 FIGS. 18-35 describe a pressure regulator which may be used within any of
 the print cartridge embodiments described herein for regulating the
 pressure of the ink chamber within the print cartridge. Hence, the
 pressure in the off-axis ink supply system may be unregulated. The
 regulator causes the ink chamber within the print cartridge to have a
 slight, but substantially constant, negative pressure (e.g., -2 to -7
 inches of water column) to prevent ink drool from the nozzles of the
 printhead. If the off-axis ink supply system is at atmospheric pressure,
 this slight negative pressure in the print cartridge also acts to draw ink
 from the off-axis ink supply system even if the location of the ink supply
 system is slightly below the print cartridge. The regulator also enables
 the use of pressurized off-axis ink supplies while maintaining the desired
 negative pressure within the ink chamber in the print cartridge. The
 regulator can be designed to provide a wide range of negative pressures
 (or back pressures) from 0 to -50 inches of water column, depending on the
 design of the printhead.
 In the embodiments shown in FIGS. 18-35, the regulator is described with
 reference to the type of print cartridge similar to print cartridge 158 in
 FIG. 15 having a septum 235 (FIG. 18); however, it is to be understood
 that a regulator using similar concepts may also be used with any of the
 other print cartridge embodiments.
 Referring to FIG. 18, reference numeral 214 generally indicates the print
 cartridge that includes a pen body 242 that is the housing for the
 cartridge and a crown 243 that forms a cap to the housing. Located at a
 remote end of the pen body is the tab head assembly 244 or THA. The THA
 includes a flex circuit 245 and a silicon die 246 that forms the print
 head 240. The THA is of conventional construction. Also located within the
 pen body 242 is a pressure regulator lever 248, an accumulator lever 250,
 and a flexible bag 252. In FIG. 18, the bag is illustrated fully inflated
 and for clarity is not shown in FIG. 19. The pressure regulator lever 248
 and the accumulator lever 250 are urged together by a spring 253, 253'
 illustrated in FIG. 19. In opposition to the spring, the bag spreads the
 two levers apart as it inflates outward. The bag is staked to a fitment
 254 that is press-fit into the crown 243. The fitment contains a vent 255
 to ambient pressure in the shape of a helical, labyrinth path. The vent
 connects and is in fluid communication with the inside of the bag so that
 the bag is maintained at a reference pressure. The helical path limits the
 diffusion of water out of the bag.
 The pressure regulator lever 248 is illustrated in detail in FIGS. 20 and
 21. Reference numeral 257 generally indicates the location of the area
 where the bag 252 directly bears against the lever. The lever 248 rotates
 about two opposed axles 258 that form the axis of rotation of the lever.
 The rotation of the lever is stopped when the lever engages the pen body
 242 as illustrated in FIG. 35. The axles are located at the ends of
 cantilevers 259 formed by deep slots so that the cantilevers and the axles
 can be spread apart during manufacture and snapped onto place on the crown
 243 as illustrated in FIG. 32. Perpendicular to the plane of the regulator
 lever 248 is a valve seat 261 and a valve seat holder 262. The valve seat
 is pressed into place on the holder and is fabricated from a resilient
 material. In response to expansion and contraction of the bag 252, the
 regulator lever 248 rotates about the axles 258, 258' and causes the valve
 seat to open and shut against a mating surface on the crown 243 as
 described below. This rotational motion controls the flow of ink into the
 ink plenum 238, FIG. 34. There is an optimization between maximizing the
 force on the valve seat and obtaining sufficient motion of the lever. In
 the embodiment actually constructed, the lever ratio between the distance
 between the centroid of the lever, generally at point 257, and the axles
 258 and the distance between the center of the valve seat and the axles
 258 is between two to one and five to one with four to one being
 preferred. The pressure regulator also includes a spring boss 264 and
 engages the spring 253, FIG. 19. The spring boss is protected during
 manufacture by two shoulders 265 which are not illustrated in FIG. 19.
 The accumulator lever 250 is illustrated in FIG. 22 and includes an
 actuation area 268 where the bag 252 directly bears against the lever. The
 lever rotates about two opposed axles 270, 270' that form an axis of
 rotation of the accumulator lever. The axles are remotely located on
 cantilevers 271 so that the axles and the cantilevers can be spread apart
 during manufacture and snapped into place on the crown 243 as described
 below. The accumulator lever also includes a spring boss 272 that engages
 the other end of the spring 253, FIG. 19. Like the spring boss 64 on the
 pressure regulator, the boss 272 on the accumulator is protected during
 manufacture by the shoulders 273. These shoulders are not illustrated in
 FIG. 19.
 The accumulator lever 250 and the bag 252 operate together to accommodate
 changes in volume due to any air that may be entrapped in the print
 cartridge 214, as well as due to any other pressure changes. The
 accumulator acts to modulate any fluctuations in the back pressure. The
 accumulator lever squeezes the bag the inside of which is at ambient
 pressure, forces air out of the bag and allows air trapped in the print
 cartridge to expand.
 Although most of the accumulation is provided by the movement of the
 accumulator lever 250 and the bag 252, there is additional accumulation
 provided by the pressure regulator lever 248 in cooperation with the
 resilient valve seat 261, FIG. 20. The valve seat acts as a spring and
 allows some movement of the regulator lever 248 while the valve is shut.
 In other words, as the back pressure in the plenum 238 (FIG. 34)
 decreases, the bag 252 exerts less force on the levers, and the spring 253
 urges the levers together. The motion of the regulator lever compresses
 the valve seat and the regulator lever shuts a little further. This
 movement of the regulator lever 248 with the bag 252 results in some
 additional air accommodation.
 It should be appreciated that the boss 272 on the accumulator lever 250 is
 closer to the axis of rotation of the accumulator lever than the boss 264,
 FIGS. 20 and 21, on the pressure regulator lever is to its axis of
 rotation. This difference in distance causes the accumulator lever to
 actuate before the pressure regulator lever moves.
 The accumulator lever 250 rotates about the axles 270 until a stop 275 on
 the lever engages a surface 276 within the crown 243, as illustrated in
 FIG. 31. The stop prevents the lever from moving too close and interfering
 with the pressure regulator lever 248 when the back pressure in the ink
 plenum drops. The accumulator lever rotates in the other direction until
 coming into contact with the pen body 242 as illustrated in FIGS. 34 and
 35.
 Referring to FIG. 19, reference numeral 253 generally indicates a helical
 extension spring that urges the two levers 248, 250 together. The spring
 is preloaded and engages the bosses 264, 272 with a coil loop at each
 distal end. Each loop is a parallel, cross-over, fully closed, centered
 loop. This spring is designed to have the least amount of variation in its
 force constant over its full range of travel so that the back pressure can
 be regulated as closely as possible.
 The fitment 254, illustrated in FIGS. 18 and 23, supports the bag 252 and
 attaches the bag to the crown 243. The fitment has a lip 278 that engages
 the crown and forms a hermetic seal with it. Within the fitment is a vent
 255 that provides communication between the interior of the bag and
 ambient pressure. At the distal end of the fitment is a raised, circular
 boss 279 and a race-track shaped outer boss 280. The bag 252 is staked to
 both bosses. The circular boss provides the main seal between the bag and
 the fitment. The race-track shaped boss provides a secondary, redundant
 sealing surface as well as provides additional support and positioning for
 the bag.
 The flexible bag 252, illustrated in FIGS. 18 and 24, expands and contracts
 as a function of the differential pressure between the back pressure in
 the ink plenum 238 (FIG. 34) and ambient pressure communicated through the
 vent 255 in the fitment 254. The bag is shown fully inflated in FIG. 24.
 The bag is designed to push against the two levers 248, 250 with maximum
 contact area through the entire range of travel of the levers. The bag is
 formed from a single sheet of multilayer film and includes two lungs 282
 that expand and contract about an axis 284. The lungs communicate with
 each other and are maintained at the same reference pressure. Each lung
 has two raised areas 283 on either side so that there are four raised
 areas in all. The two inner raised areas that bear against each other are
 not shown in FIG. 24 but are indicated by reference numerals 283' and
 283". The side opposite the fitment contains a raised communication
 channel 285, FIGS. 26, 28, between the raised areas which allows a path
 for air to flow when the bag is completely deflated. The raised areas are
 thinner that the rest of the bag and provide greater compliance to the
 travel of the levers and the motion of the lungs about the axis 284. The
 raised areas are designed to eliminate relative motion or sliding of the
 bag with respect to the levers. In systems that actuate on very slight
 pressures, this undesirable affect is called hysteresis. The combination
 of the lungs and raised areas provides extra material into which the bag
 can expand as well as maximizes the change in ink volume displaced by the
 bag with any change in differential pressure.
 The process for making the bag 252 is illustrated in FIGS. 25-30. First, a
 sheet 287 of flat film is cut to size, FIG. 25. The film is a multilayer
 structure between one and three mils (one rail is 25.4 microns) thick, 1.5
 mils being the preferred thickness. In the preferred embodiment, three
 materials show acceptable performance: (1) PE/tie/PVDC/tie/PE, (2)
 PE/tie/PVDF/tie/PE, and (3) PE/tie/EVOH/tie/PE. PVDC is polyvinylidene
 chloride; DOW version is known as SARAN. EVOH is ethylene-vinyl alcohol
 copolymer. PE is polyethylene. Tie is a layer used to bond the dissimilar
 materials together. PVDF is polyvinylidenefluoride and is sold under the
 trade name of Kynar.TM.. Next, the sheet is placed over a die plate, and
 heat and vacuum are applied to form the four raised areas 288, 288', FIG.
 26. Note that two of the four raised areas or pockets 288' are in
 communication. Thereafter, the sheet 287 is heat staked to the two bosses
 279, 280 on the fitment 254, FIG. 23, as shown in FIG. 27. Next, a hole
 289 is made in the film in the center of the circular boss 279 to
 establish communication to the vent 255 in the fitment. The sheet is then
 folded along axis 290 and the perimeter of the bag where the margins came
 together is staked. This staking occurs along the three open seams and is
 indicated by reference numeral 291 in FIG. 29. The perimeter of the bag is
 then trimmed. Thereafter, the bag is folded along the longitudinal axis
 296 of the fitment as illustrated in FIG. 29. This forms the two lungs
 282, 282' in the bag. Referring to FIGS. 29, 30, and 24, the longitudinal
 axis 296 of the fitment and the line of folding in FIG. 29 is parallel to
 the axis 284 of rotation of the two lungs including expansion/contraction
 of the bag.
 FIG. 31 illustrates the bottom-side of the crown 243 which includes a valve
 face 293 and the tapered nozzle or orifice 292 through which ink enters
 the plenum 238. The valve face mates with the valve seat 261, FIG. 20, on
 the pressure regulator lever 248. This mating is also shown in FIG. 32.
 Ink flows through the fluid interconnect, the septum 235, and the orifice
 292. The tapered orifice 292 reduces the area of contact between the valve
 seat 261 and the valve face 293 to thereby increase the valve sealing
 pressure.
 At orifice 292, the back pressure within the plenum 238 (FIG. 34) is
 controlled by the lever 248. Next to the valve face 293 on the crown 243
 is a circular boss 294 that receives the lip 278 on the fitment 254, FIG.
 24. The boss 294 and the lip form a hermetic seal. The axles 258, 258',
 FIG. 21, on the pressure regulator lever 248 are snapped into the journals
 295, 295' as permitted by the cantilevered construction described above.
 In like manner the axles 270, 270' on the accumulator lever 250 are
 received in the journals 297, 297', FIG. 31. Also located on the bottom
 side of the crown is the surface 276 that engages the stop 275, FIG. 22,
 on the accumulator lever 250. The stop 275 and the surface 276 prevent the
 accumulator lever from interfering with the pressure regulator lever 248.
 The operation of the print cartridge 214 is illustrated in FIGS. 33, 34,
 and 35. In the initial condition of the cartridge, there is no ink within
 the ink plenum 238, and the bag 252 is limp. The back pressure in the
 plenum equals ambient pressure. The spring 253 urges the two levers 248,
 250 fully together.
 Next, a hollow needle is inserted into the septum 235 and a vacuum is drawn
 on the nozzles in the print head 240 (FIG. 18) to draw ink into the print
 cartridge. In response to this vacuum, the accumulator lever 250 moves
 first, and the bag begins to expand as shown in FIG. 24. The accumulator
 lever continues to rotate about its axis of rotation until it engages the
 side wall of the pen body 242 as shown in FIG. 24. At this point the
 pressure regulator lever 248 begins to move, and ink begins to enter the
 plenum 238 through orifice 292, FIG. 31.
 The regulator lever 248 can rotate about its axis of rotation until it
 engages the side wall of the pen body 242 as shown in FIG. 35. This is the
 full-open position of the valve. The regulator lever moves between the
 states illustrated in FIGS. 34 and 35 depending on the speed of printing
 and how fast ink is required by the print head.
 Once the plenum 238 is filled with ink or printing has stopped, the
 pressure regulator lever 248 will slowly rotate and close the orifice at
 the urging of the spring 253. The levers 248 and 250 return to the state
 illustrated in FIG. 34 which is the normal or steady state condition of
 the print cartridge. This state occurs just prior to or subsequent to
 printing.
 Referring to FIG. 34, reference numeral 298 indicates an air bubble that
 has entered the ink plenum 238. If the print cartridge is subjected to an
 elevation in temperature or increased altitude, the air bubble will expand
 in the plenum. The expansion of the air bubble will be compensated for by
 the contraction of the bag 252 due to a pressure change caused by a volume
 change of the bubble which in turn causes the accumulator lever to move
 from the state illustrated in FIG. 34 toward that illustrated in FIG. 33.
 In addition, there will be some accompanying motion of the regulator lever
 248 because of the resilience of the valve seat 261. On the other hand, if
 the air bubble contracts, the bag will expand in response and the pressure
 regulator lever 248 will open the orifice and admit ink onto the plenum.
 In other words, any expansion or contraction of an air bubble will cause
 the bag to compensate in reverse, that is by contracting to expansion and
 expanding to contraction. Each of the levers tracks the motion of the bag
 and the accumulator lever 250 rotates before the regulator lever 248
 because of the difference in lever arm distances.
 When the off-axis ink supply (e.g., supply 30 in FIG. 1) is depleted of
 ink, the levers 248, 250 rotate to the full-open position in FIG. 35 and
 the print head stops ejecting ink.
 FIG. 36 is an exploded view of a non-pressurized ink supply cartridge 300
 such as shown in FIGS. 2, 9B, and 12B. Such an ink supply cartridge 300 is
 simply removed from the ink supply support (e.g., support 144 in FIG. 12B)
 and disposed of once its supply of ink has been depleted. The connection
 of such an ink supply cartridge 300 to the fluid interconnect has been
 described with respect to FIG. 12B.
 The non-pressurized ink supply cartridge 300 consists of a collapsible ink
 bag 302 and two rigid plastic housing members 303 and 304. Ink bag 302 may
 be formed of a flexible film such as Mylar or EVA, a multi-layer film
 having layers of low density polyethylene, adhesive, and metallized
 polyethylene terephthalate, or the nine-layer film described in U.S. Pat.
 No. 5,450,112, assigned to the present assignee and incorporated herein by
 reference. The ends of ink bag 302 may be heat-staked or ultrasonically
 welded to housing member 303 or 304 to limit movement of bag 302.
 Coded tabs 305 align with slots formed in the ink supply support to ensure
 the proper color ink supply cartridge is inserted into the correct stall
 of the ink supply support. In one embodiment, the ink supply support also
 latches onto tab 305, using a spring-loaded latch, to secure cartridge 300
 and to provide tactile feedback to the user that cartridge 300 is properly
 installed.
 A plastic ink bag fitment 306 is partially inserted through an opening 307
 in ink bag 302 and sealed with respect to opening 307 by glue or heat
 fusing. A poppet 308 extends from fitment 306. Bag fitment 306 is held
 firmly in place by a slot 307 formed in the plastic housing members 303
 and 304.
 A poppet spring 309 is inserted through a hole 310 in poppet 308 followed
 by a poppet ball 311. Ball 311 may be stainless steel or plastic.
 An end 312 of a rubber septum 313 is then inserted into hole 310 in poppet
 308. Septum 313 is then crimped and secured to poppet 308 using a crimped
 cap 314.
 Septum 313 has a slit 315 formed through its center through which a hollow
 needle 142 (FIG. 12B), in fluid connection with a print cartridge, is
 inserted as shown in FIG. 17. Slit 315 in septum 313 is automatically
 urged closed by the resiliency of septum 313 when the needle is removed.
 Poppet spring 309 and poppet ball 311 serve to provide added assurance that
 no ink will leak through slit 315 in septum 313. When there is no needle
 inserted through slit 315, poppet spring 309 urges poppet ball 311 against
 the closed slit 315 so that ball 311 in conjunction with the closing of
 slit 315 provides a seal against ink leakage.
 It is possible to design the fluid interconnect using a septum without the
 poppet, or a poppet without the septum. A septum without the poppet will
 reliably seal around a needle with a radial seal. However, when the ink
 supply with a septum has been installed in the printer for a long time,
 the septum will tend to take on a compression set. Upon removal, the
 septum may not completely reseal itself. If the supply is tipped or
 dropped, ink may leak out. A poppet valve (by itself) has the advantage
 (relative to a septum) of self-sealing without a compression set issue.
 However, it is less reliable in that it does not seal around the needle.
 Thus, to ensure a leak-tight fluid interconnection with the cartridge,
 some kind of face seal must be established. In addition, poppet valves
 vary in reliability when the surface they seal against is hard
 plastic--small imperfections in the sealing surface tend to lead to leaks.
 The combination of the septum/poppet valve overcomes these limitations by
 utilizing the advantages of both: the septum's very good sealing around
 the needle while eliminating the compression set issue. Additionally, the
 inside surface of the septum provides a compliant sealing surface for the
 poppet valve that is less sensitive to imperfections.
 In the preferred embodiment, an integrated circuit sensor/memory 316 is
 permanently mounted to ink supply cartridge 300. This circuit provides a
 number of functions, including verifying insertion of the ink supply,
 providing indication of remaining ink in the supply, and providing a code
 to assure compatibility of the ink supply with the rest of the system.
 In an alternate embodiment, ink bag 302 is provided with a positive
 pressure. This enables the tubes connecting the ink supply to the print
 cartridges to be thinner and also allows the ink supply station to be
 located well below the print cartridges. By providing ink bag 302 with
 rigid side panels 318 to distribute the spring force, a spring can be used
 to urge the sides of ink bag 302 together to create a positive internal
 pressure. Bow springs, spiral springs, foam, a gas, or other resilient
 devices may supply the spring force. In another embodiment, ink bag 302
 may be pressurized by an intermittent pressure source, such as a gas.
 Alternatively, a pump within the ink supply may be used as described in
 described in U.S. patent application Ser. No. 08/706,121, filed Aug. 30,
 1996, now U.S. Pat. No. 5,966,155, entitled "Inkjet Printing System with
 Off-Axis Ink Supply Having Ink Path Which Does Not Extend above Print
 Cartridge," which is herein incorporated by reference.
 Upon depletion of the ink from the reservoir 324, or for any other reason,
 the ink supply 320 can be easily removed from the docking bay 338. Upon
 removal, the fluid outlet 328 and the fluid inlet 342 are closed to help
 prevent any residual ink from leaking into the printer or onto the user.
 The ink supply may then be discarded or stored for reinstallation at a
 later time. In this manner, the present ink supply 320 provides a user of
 an ink-jet printer a simple, economical way to provide a reliable and
 easily replaceable supply of ink to an inkjet printer.
 The illustrated plastic sheet is flexible to allow the volume of the
 reservoir to vary as ink is depleted from the reservoir. This helps to
 allow withdrawal and use of all of the ink within the reservoir by
 reducing the amount of back pressure created as ink is depleted from the
 reservoir.
 The print cartridge, carriages, and off-axis ink delivery systems described
 herein may be used in various combinations to provide ink to the nozzles
 of the printheads in the print cartridges. As one example, any of the
 print cartridges described may be used with either the pressurized or
 unpressurized ink supply cartridges. The ink supply cartridges may be
 arranged in a printer for convenient access, ease of use, maximum
 utilization of space, and allowing for the required delivered ink volume.
 The pressure regulator, being integral with the print cartridge in the
 preferred embodiment, allows printhead performance to be independent of
 the relative heights of the ink supply and printhead.
 The lowest cost system will typically be one with unpressurized supplies.
 However, pressurization may be required for some situations. This is best
 understood by considering causes of dynamic and static pressure changes.
 The static pressure in the printhead is defined as that which exists when
 the printhead is parked and not operating and is typically optimally set
 to -2 to -6 inches of water column by the spring in the regulator.
 However, if the ink supplies are located more than 6 inches below the
 printhead, then the regulator will always be open (assuming the above set
 point range), and the static pressure will always be the difference in
 height. To make matters worse, the pressure of concern is dynamic, defined
 as the pressure experienced in the printhead during operation. Thus, the
 actual dynamic pressure will be an even larger negative number and will be
 outside the regulator range.
 Pressurizing the ink supply will solve this problem. This can be done by
 the aforementioned method or by using springs to provide constant ink
 supply pressure. This can be done to counteract the relative heights, and
 other factors that affect the dynamic pressure drop. Factors that increase
 the dynamic pressure drop include rate of ink usage by the printhead,
 decreasing tubing diameter, increasing tubing length, and increasing ink
 viscosity. The pressurization must be increased until the pressure is
 entirely controlled by the regulator to within the print quality driven
 pressure specification.
 When in use in the printer 10, the print cartridges shown in FIGS. 5A-5C,
 10 and 15 are in fluid communication with an off-carriage ink supply 31-34
 that is releasably mounted in an ink supply station 30. Without this fluid
 communication, the new off-axis design print cartridges have very little
 internal ink capacity in their reservoirs and these print cartridges 50
 can expel only approximately 1 cc of ink. However, when a new cartridge 50
 is manufactured, it needs to be run through an automated print quality
 tester. This allows the manufacturer to screen out cartridges failing to
 meet minimum quality standards. Additional production line processes that
 use ink may include a nozzle down flush, wetfiring, and reprinting. This
 testing requires the use of ink. With the new off-axis cartridge designs,
 the amount of ink available internally may not be enough to make it
 through the automated print quality tester and the other uses of ink
 described above.
 Moreover, prior to printer installation by the user, the cartridge is in
 transit and in storage. Therefore, there is also a need to provide a means
 of lubricating and protecting the hollow needle 60 and the inlet port on
 the print cartridge 50. In particular, the hollow needle 60 and inlet port
 should be protected from drying, leaking ink and air ingestion.
 Shown in FIG. 37 is an embodiment of a fluidic coupling or adapter 400 of
 the present invention. Fluidic coupling or adapter 400 has a central or
 body portion 402 and first and second shoulder portions 404, 406,
 respectively. First shoulder 404 includes a septum 408 on its end for
 interfacing with the hollow needle 60 and inlet port on the print
 cartridge. A second septum (not shown) is included at the end of second
 shoulder 406 for connecting to a needle on the production line ink supply.
 The fluidic coupling or adapter 400 has guides 412 for guiding and
 aligning the fluidic coupling 400 when inserting the coupling into the
 print cartridge. Also shown is a handle 414 attached to the body 402 of
 the fluidic coupling 400.
 FIG. 38 shows fluidic coupling or adapter 400 installed in a print
 cartridge 420. Print cartridge 420 has a shroud 422 which surrounds and
 protects the hollow needle (not shown). Print cartridge 420 has an opening
 424 in the shroud 422 for receiving the handle 414 of the fluidic coupling
 or adapter 400. Shroud 422 has an inner taper which mates with a
 corresponding taper on the shoulder 404 and guides 412 to receive and
 center fluidic coupling or adapter 400 with respect to needle 60 and hold
 fluidic coupling or adapter 400 by friction when it is inserted upwardly
 into shroud 422. It will be appreciated that any type of latching method
 could be used to secure the coupling 400 to the printhead. The printhead
 nozzle array 416 located at the bottom of print cartridge 420 ejects ink
 downward in direction 418.
 Another embodiment of the fluidic coupling or adapter 400 is shown in FIG.
 40. In this embodiment, the internal chamber 430 contains is fined with
 foam 431 which is saturated with Ink. In the embodiment shown in FIG. 41
 the internal chamber contains a bladder 432. The walls 434 of the bladder
 432 are made of an elastic material. In FIG. 42 is shown an embodiment
 wherein there is a spring bag 436 located in the internal chamber 430. The
 spring bag walls 438 are made of a material such a flexible film such as
 Mylar or EVA, a multi-layer film having layers of low density
 polyethylene, adhesive, and metallized polyethylene terephthalate, or the
 nine-layer film described in U.S. Pat. No. 5,450,112, assigned to the
 present assignee and incorporated herein by reference. The ends of Ink
 bladder or the Ink bag may be heat-staked or ultrasonically welded to
 fluidic coupling 400 to limit movement. The spring bag 436 is biased open
 by a spring 442 which presses on side plates 440 located on the inner
 surface of the bag walls 438. FIG. 39 is a cross-sectional view of print
 cartridge 420 taken along line A--A in FIG. 38. FIG. 39 shows the hollow
 needle 60 passing through septum 408 into the internal chamber 430 located
 within the body 402 of fluidic coupling or adapter 400. In the embodiment
 shown in FIG. 39, internal chamber 430 is hollow and acts as fluid conduit
 for ink supplied from a needle (not shown) inserted through septum 410.
 In the embodiments shown in FIGS. 41 and 42, the bladder 432 and spring bag
 436 act as a compliant member. As ink is withdrawn from the bladder or
 spring bag, they collapse in the chamber 430. This compliance produces
 back pressure in the bladder or spring bag, which increases as the bladder
 or spring bag collapses. See, for example, U.S. Pat. No. 4,500,895 (ink
 bladder type reservoir) and U.S. Pat. No. 5,359,353 (spring-bag type
 reservoir) all assigned to the assignee of the present invention and
 incorporated herein by reference.
 The embodiments shown in FIGS. 40, 41 and 42, in addition to providing the
 functions indicated above, provides an ink reservoir that can travel with
 the cartridge during production, eliminating the need to refill the print
 cartridge. As can be appreciated, this reservoir can be sized to hold
 anywhere from 0.5 to 50 cc of ink. Thus, it could even provide an
 on-carriage auxiliary reservoir, eliminating the need for an off-axis ink
 supply.
 Shown in FIGS. 43A and 43B are different shapes for the fluidic coupling of
 the present invention. It will be appreciated that other shape variations
 are possible and within the scope of the present invention.
 The embodiments of the fluidic coupling or adapter 400 shown in FIGS. 37-42
 have the following functions: (1) prevention of ink leakage from the
 needle and inlet port on the print cartridge, (2) prevention of air from
 being ingested into the print cartridge, (3) provides an auxiliary
 on-board ink reservoir, and (4) provides an inlet and fluidic coupling
 from another ink supply source such as, for example, on the print
 cartridge production line.
 Shown in FIG. 44 is an embodiment of the present invention which provides
 functions 1-3 described above but does not provide a fluidic coupling to
 another ink supply. In this embodiment there is only one septum 408 for
 interfacing with the needle 60 on the print cartridge 50. Below the ink
 saturated foam 431 is unsaturated foam. Vent holes 452 are provide to
 allow entry of air as ink is withdrawn. Optionally a material such as
 Gortex which allows the passage of air but not liquid may be used at the
 interface of the saturated foam. While the embodiment shown in FIG. 44 has
 a foam filled internal chamber, the bladder and spring bag embodiments
 described above could also be utilized.
 In the embodiments shown above, the shape of the body 402 and the shoulders
 404, 406 of the fluidic coupling 400 are cylindrical any other shape could
 be utilized. Moreover the shape of the body 402 and the shoulders 404, 406
 need not be the same. The only restriction being the ability to mate the
 shoulder 404 of the fluidic coupling 400 to the needle 60 and shroud 422
 to effectuate a seal between the fluidic coupling 400 and the inlet port
 of the print cartridge 420.
 In the embodiments shown above having the hollow needle extending from the
 print cartridge, the needle may be replaced with a septum, and the septum
 on the fluidic coupler replaced with a hollow needle. This is also the
 case for the septum which connects to an auxiliary ink supply.
 As a result of these design options, the integral pressure regulator offers
 a wide range of product implementations other than those illustrated in
 FIGS. 1A and 1B. For example, such ink delivery systems may be
 incorporated into an inkjet printer used in a facsimile machine 500 as
 shown in FIG. 19, where a scanning cartridge 502 and an off-axis ink
 delivery system 504, connected via tube 506, are shown in phantom outline.
 FIG. 20 illustrates a copying machine 510, which may also be a combined
 facsimile/copying machine, incorporating an ink delivery system described
 herein. Scanning print cartridges 502 and an off-axis ink supply 504,
 connected via tube 506, are shown in phantom outline.
 FIG. 21 illustrates a large-format printer 516 which prints on a wide,
 continuous paper roll supported by tray 518. Scanning print cartridges 502
 are shown connected to the off-axis ink supply 504 via tube 506.
 Facsimile machines, copy machines, and large format machines tend to be
 shared with heavy use. They are often used unattended and for large
 numbers of copies. Thus, large capacity (50-500 cc) ink supplies will tend
 to be preferred for these machines. In contrast, a home printer or
 portable printer would be best with low capacity supplies in order to
 minimize product size and cost. Thus, the product layouts shown in FIGS.
 1A and 1B are most appropriate for such smaller form factor or lower cost
 applications.
 While particular embodiments of the present invention have been shown and
 described, it will be obvious to those skilled in the art that changes and
 modifications may be made within departing from this invention in its
 broader aspects and, therefore, the appended claims are to encompass
 within their scope all such changes and modifications as fall within the
 true spirit and scope of this invention.