US 6,209,989 B1Grant
Dual chamber single actuator ink jet printing mechanism
Issue Date:2001-04-03
•15 Claims
•18 Drawing Sheets
Abstract
An apparatus for ejecting fluids from a nozzle chamber is disclosed including a nozzle chamber having at least two fluid ejection apertures defined in the walls of the chamber; a moveable paddle vane located between the fluid ejection apertures; an actuator mechanism attached to the moveable paddle vane and adapted to move the paddle vane in a first direction so as to cause the ejection of fluid drops out of a first fluid ejection aperture and to further move the paddle vane in a second alternative direction so as to cause the ejection of fluid drops out of a second fluid ejection aperture. The actuator can comprise a thermal actuator having at least two heater elements with a first of the elements being actuated to cause the paddle vane to move in a first direction and a second heater element being actuated to cause the paddle vane to move in a second direction. The heater elements preferably have a high bend efficiency. The paddle vane and the actuator can be joined at a fulcrum pivot point, the fulcrum pivot point having a thinned portion of the nozzle chamber wall. The actuator can include one end fixed to a substrate and a second end containing a bifurcated tongue having two leaf portions on each end of the bifurcated tongue the leaf portions interconnecting to a corresponding side of the paddle with the tongue such that, upon actuation of the actuator, one of the leaf portions pulls on the paddle end.
Metadata
Assignee
- Silverbrook Research PTY LTD
Inventor
- Kia Silverbrook
Application Information
Application Number:US 09/112,813
Filing Date:1998-07-10
Priority Date:1997-12-12
Art Unit:7
Classifications
IPC:
B41J 204B41J 2135B41J 2015
Field of Search:
347 44347 54347 47347 20
Patent Drawings (18 sheets)
Description
FIELD OF THE INVENTION
[0002] The present invention relates to the field of inkjet printing and in particular discloses a dual chamber single actuator inkjet printer.
BACKGROUND OF THE INVENTION
[0003] Many different types of printing have been invented, a large number of which are presently in use. The known forms of print have a variety of methods for marking the print media with a relevant marking media. Commonly used forms of printing include offset printing, laser printing and copying devices, dot matrix type impact printers, thermal paper printers, film recorders, thermal wax printers, dye sublimation printers and ink jet printers both of the drop on demand and continuous flow type. Each type of printer has its own advantages and problems when considering cost, speed, quality, reliability, simplicity of construction and operation etc.
[0004] In recent years, the field of ink jet printing, wherein each individual pixel of ink is derived from one or more ink nozzles has become increasingly popular primarily due to its inexpensive and versatile nature.
[0005] Many different techniques on ink jet printing have been invented. For a survey of the field, reference is made to an article by J Moore, “Non-Impact Printing: Introduction and Historical Perspective”, Output Hard Copy Devices, Editors R Dubeck and S Sherr, pages 207-220 (1988).
[0006] Ink Jet printers themselves come in many different types. The utilization of a continuous stream ink in ink jet printing appears to date back to at least 1929 wherein U.S. Pat. No. 1,941,001 by Hansell discloses a simple form of continuous stream electrostatic ink jet printing.
[0007] U.S. Pat. 3,596,275 by Sweet also discloses a process of a continuous ink jet printing including the step wherein the ink jet stream is modulated by a high frequency electro-static field so as to cause drop separation. This technique is still utilized by several manufacturers including Elmjet and Scitex (see also U.S. Pat, No. 3,373,437 by Sweet et al)
[0008] Piezo-electric ink jet printers are also one form of commonly utilized ink jet printing device. Piezo-electric systems are disclosed by Kyser et. al. in U.S. Pat. No. 3,946,398 (1970) which utilizes a diaphragm mode of operation, by Zolten in U.S. Pat. No. 3,683,212 (1970) which discloses a squeeze mode of operation of a piezo electric crystal, Stemme in U.S. Pat. No. 3,747,120 (1972) discloses a bend mode of piezo-electric operation, Howkins in U.S. Pat. No. 4,459,601 discloses a Piezo electric push mode actuation of the ink jet stream and Fischbeck in U.S. Pat. No. 4,584,590 which discloses a sheer mode type of piezo-electric transducer element.
[0009] Recently, thermal ink jet printing has become an extremely popular form of ink jet printing. The ink jet printing techniques include those disclosed by Endo et al in GB 2007162 (1979) and Vaught et al in U.S. Pat. No. 4490728. Both the aforementioned references disclosed ink jet printing techniques rely upon the activation of an electrothermal actuator which results in the creation of a bubble in a constricted space, such as a nozzle, which thereby causes the ejection of ink from an aperture connected to the confined space onto a relevant print media. Printing devices utilizing the electro-thermal actuator are manufactured by manufacturers such as Canon and Hewlett Packard.
[0010] As can be seen from the foregoing, many different types of printing technologies are available. Ideally, a printing technology should have a number of desirable attributes. These include inexpensive construction and operation, high speed operation, safe and continuous long term operation etc. Each technology may have its own advantages and disadvantages in the areas of cost, speed, quality, reliability, power usage, simplicity of construction operation, durability and consumables.
[0011] In any inkjet printing arrangement, especially where page width printheads are being constructed and utilized, it is important to minimize the size of the structure of each ejection nozzle. As the inkjet nozzles may be constructed in the form of multiple nozzles at a time on for example, silicon wafer, by minimizing the size of each nozzle, it is possible to fit more nozzles and hence more printheads on a single silicon wafer. It is therefore advantageous to provide for an arrangement that is of a compact size and utilizes low energy levels so as to minimize the energy requirements in the actuation of inkjet printheads.
SUMMARY OF THE INVENTION
[0012] It is an object of the present invent to provide an efficient dual chamber single vertical actuator inkjet printer.
[0013] In accordance with a first aspect of the present invention, there is provided an apparatus for ejecting fluids from a nozzle chamber comprising a nozzle chamber having at least two fluid ejection apertures defined in the walls of the chamber; a moveable paddle vane located between the fluid ejection apertures; an actuator mechanism attached to the moveable paddle vane and adapted to move the paddle vane in a first direction so as to cause the ejection of fluid drops out of a first fluid ejection aperture and to further move the paddle vane in a second alternative direction so as to cause the ejection of fluid drops out of a second fluid ejection aperture.
[0014] The actuator can comprise a thermal actuator having at least two heater elements with a first of the elements being actuated to cause the paddle vane to move in a first direction and a second heater element being actuated to cause the paddle vane to move in a second direction. The heater elements preferably have a high bend efficiency wherein the bend efficiency is defined as the youngs modulus times the coefficient of thermal expansion divided by the density and by the specific heat capacity.
[0015] The heater elements can be arranged on opposite sides of a central arm, the central arm having a low thermal conductivity.
[0016] The paddle vane and the actuator can be joined at a fulcrum pivot point, the fulcrum pivot point comprising a thinned portion of the nozzle chamber wall. The actuator can include one end fixed to a substrate and a second end containing a bifurcated tongue having two leaf portions on each end of the bifurcated tongue, the leaf portions interconnecting to a corresponding side of the paddle with the tongue such that, upon actuation of the actuator, one of the leaf portions pulls on the paddle end.
[0017] The apparatus can further comprise a fluid supply channel connecting the nozzle chamber with a fluid supply for supplying fluid to the nozzle chamber, the connection being in a wall of the chamber substantially adjacent the quiescent position of the paddle vane. The connection can comprise a slot defined in the wall of the chamber, the slot having similar dimensions to a cross-sectional profile of the paddle vane. The central arm can comprise substantially glass.
[0018] The apparatus is ideally suited for use in the form of ink jet printer. Each fluid ejection aperture preferably includes a rim defined around an outer surface thereof.
[0019] Preferably, a multiplicity of apparatuses can be arranged such that the fluid ejection apertures are grouped together spatially into spaced apart rows and fluid is ejected from the fluid ejection apertures of each of the rows in phases. The nozzle chambers can be further grouped into multiple ink colors and with each of the nozzles being supplied with a corresponding ink color.
[0020] In accordance with a second aspect of the present invention, there is provided a method of ejecting drops of fluid from a nozzle chamber having at least two nozzle apertures defined in the wall of the nozzle chambers utilizing a moveable paddle vane attached to an actuator mechanism, the method comprising the steps of actuating the actuator to cause the moveable paddle to move in a first direction so as to eject drops from a first of the nozzle apertures; and actuating the actuator causing the moveable paddle to move in a second direction so as to eject drops from a second of the nozzle apertures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Notwithstanding any other forms which may fall within the scope of the present invention, preferred forms of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:
[0022] FIGS. 1-5 comprise schematic illustrations of the operation of the preferred embodiment;
[0023] FIG. 6 illustrates a side perspective view, of a single nozzle arrangement of the preferred embodiment.
[0024] FIG. 7 illustrates a perspective view, partly in section of a single nozzle arrangement of the preferred embodiment;
[0025] FIGS. 8-27 are cross sectional views of the processing steps in the construction of the preferred embodiment;
[0026] FIG. 28 illustrates a part of an array view of a portion of a printhead as constructed in accordance with the principles of the present invention;
[0027] FIG. 29 provides a legend of the materials indicated in FIG. 30 to 42; and
[0028] FIG. 30 to FIG. 44 illustrate sectional views of the manufacturing steps in one form of construction of an ink jet printhead nozzle.
DESCRIPTION OF PREFERRED AND OTHER EMBODIMENTS
[0029] In the preferred embodiment, there is provided an inkjet printhead having an array of nozzles wherein the nozzles are grouped in pairs and each pair is provided with a single actuator which is actuated so as to move a paddle type mechanism to force the ejection of ink out of one or other of the nozzle pairs. The paired nozzles eject ink from a single nozzle chamber which is resupplied by means of an ink supply channel. Further, the actuator of the preferred embodiment has unique characteristics so as to simplify the actuation process.
[0030] Turning initially to FIGS. 1 to 5, there will now be explained the principles of operation of the preferred embodiment. In the preferred embodiment, a single nozzle chamber 1 is utilized to supply ink two ink ejection nozzles 2, 3. Ink is resupplied to the nozzle chamber 1 via means of an ink supply channel 5. In its quiescent position, to ink menisci 6, 7 are formed around the ink ejection holes 2, 3. The arrangement of FIG. 1 being substantially axially symmetric around a central paddle 9 which is attached to an actuator mechanism.
[0031] When it is desired to eject ink out of one of the nozzles, say nozzle 3, the paddle 9 is actuated so that it begins to move as indicated in FIG. 2. The movement of paddle 9 in the direction 10 results in a general compression of the ink on the right hand side of the paddle 9. The compression of the ink results in the meniscus 7 growing as the ink is forced out of the nozzles 3. Further, the meniscus 6 undergoes an inversion as the ink is sucked back on the left hand side of the actuator 10 with additional ink 12 being sucked in from ink supply channel 5. The paddle actuator 9 eventually comes to rest and begins to return as illustrated in FIG. 3. The ink 13 within meniscus 7 has substantial forward momentum and continues away from the nozzle chamber while the paddle 9 causes ink to be sucked back into the nozzle chamber. Further, the surface tension on the meniscus 6 results in further in flow of the ink via the ink supply channel 5. The resolution of the forces at work in the resultant flows results in a general necking and subsequent breaking of the meniscus 7 as illustrated in FIG. 4 wherein a drop 14 is formed which continues onto the media or the like. The paddle 9 continues to return to its quiescent position.
[0032] Next, as illustrated in FIG. 5, the paddle 9 returns to its quiescent position and the nozzle chamber refills by means of surface tension effects acting on meniscuses 6, 7 with the arrangement of returning to that showing in FIG. 1. When required, the actuator 9 can be activated to eject ink out of the nozzle 2 in a symmetrical manner to that described with reference to FIG. 1-5. Hence, a single actuator 9 is activated to provide for ejection out of multiple nozzles. The dual nozzle arrangement has a number of advantages including in that movement of actuator 9 does not result in a significant vacuum forming on the back surface of the actuator 9 as a result of its rapid movement. Rather, meniscus 6 acts to ease the vacuum and further acts as a “pump” for the pumping of ink into the nozzle chamber. Further, the nozzle chamber is provided with a lip 15 (FIG. 2) which assists in equalizing the increase in pressure around the ink ejection holes 3 which allows for the meniscus 7 to grow in an actually symmetric manner thereby allowing for straight break off of the drop 14.
[0033] Turning now to FIGS. 6 and 7, there is illustrated a suitable nozzle arrangement with FIG. 6 showing a single side perspective view and FIG. 7 showing a view, partly in section illustrating the nozzle chamber. The actuator 20 includes a pivot arm attached at the post 21. The pivot arm includes an internal core portion 22 which can be constructed from glass. On each side 23, 24 of the internal portion 22 is two separately control heater arms which can be constructed from an alloy of copper and nickel (45% copper and 55% nickel). The utilization of the glass core is advantageous in that it has a low coefficient thermal expansion and coefficient of thermal conductivity. Hence, any energy utilized in the heaters 23, 24 is substantially maintained in the heater structure and utilized to expand the heater structure and opposed to an expansion of the glass core 22. Structure or material chosen to form part of the heater structure preferably has a high “bend efficiency”. One form of definition of bend efficiency can be the youngs modulus times the coefficient of thermal expansion divided by the density and by the specific heat capacity.
[0034] The copper nickel alloy in addition to being conductive has a high coefficient of thermal expansion, a low specific heat and density in addition to a high young's modulus. It is therefore a highly suitable material for construction of the heater element although other materials would also be suitable.
[0035] Each of the heater elements can comprise a conductive out and return trace with the traces being insulated from one and other along the length of the trace and conductively joined together at the far end of the trace. The current supply for the heater can come from a lower electrical layer via the pivot anchor 21. At one end of the actuator 20, there is provided a bifurcated portion 30 which has attached at one end thereof to leaf portions 31, 32.
[0036] To operate the actuator, one of the arms 23, 24 eg. 23 is heated in air by passing current through it. The heating of the arm results in a general expansion of the arm. The expansion of the arm results in a general bending of the arm 20. The bending of the arm 20 further results in leaf portion 32 pulling on the paddle portion 9. The paddle 9 is pivoted around a fulcrum point by means of attachment to leaf portions 38, 39 which are generally thin to allow for minor flexing. The pivoting of the arm 9 causes ejection of ink from the nozzle hole 40. The heater is deactivated resulting in a return of the actuator 20 to its quiescent position and its corresponding return of the paddle 9 also to is quiescent position. Subsequently, to eject ink out of the other nozzle hole 41, the heater 24 can be activated with the paddle operating in a substantially symmetric manner.
[0037] It can therefore be seen that the actuator can be utilized to move the paddle 9 on demand so as to eject drops out of the ink ejection hole eg. 40 with the ink refilling via an ink supply channel 44 located under the paddle 9.
[0038] The nozzle arrangement of the preferred embodiment can be formed on a silicon wafer utilizing standard semi-conductor fabrication processing steps and micro-electromechanical systems (MEMS) construction techniques.
[0039] For a general introduction to a micro-electro mechanical system (MEMS) reference is made to standard proceedings in this field including the proceeding of the SPIE (International Society for Optical Engineering) including volumes 2642 and 2882 which contain the proceedings of recent advances and conferences in this field.
[0040] Preferably, a large wafer of printheads is constructed at any one time with each printhead providing a predetermined pagewidth capabilities and a single printhead can in turn comprise multiple colors so as to provide for full color output as would be readily apparent to those skilled in the art.
[0041] Turning now to FIG. 8-FIG. 27 there will now be explained one form of fabrication of the preferred embodiment. The preferred embodiment can start as illustrated in FIG. 8 with a CMOS processed silicon wafer 50 which can include a standard CMOS layer 51 including of the relevant electrical circuitry etc. The processing steps can then be as follows:
[0042] 1. As illustrated in FIG. 9, a deep etch of the nozzle chamber 51 is performed to a depth of 25 micron;
[0043] 2. As illustrated in FIG. 10, a 27 micron layer of sacrificial material 52 such as aluminum is deposited;
[0044] 3. As illustrated in FIG. 11, the sacrificial material is etched to a depth of 26 micron using a glass stop so as to form cavities using a paddle and nozzle mask.
[0045] 4. As illustrated in FIG. 12, a 2 micron layer of low stress glass 53 is deposited.
[0046] 5. As illustrated in FIG. 13, the glass is etched to the aluminum layer utilizing a first heater via mask.
[0047] 6. As illustrated in FIG. 14, a 2 micron layer of 60% copper and 40% nickel is deposited 55 and planarized (FIG. 15) using chemical mechanical planarization (CMP).
[0048] 7. As illustrated in FIG. 16, a 0.1 micron layer of silicon nitride is deposited 56 and etched using a heater insulation mask.
[0049] 8. As illustrated in FIG. 17, a 2 micron layer of low stress glass 57 is deposited and etched using a second heater mask.
[0050] 9. As illustrated in FIG. 18, a 2 micron layer of 60% copper and 40% nickel is deposited 55 and planarized (FIG. 19) using chemical mechanical planarization.
[0051] 10. As illustrated in FIG. 20, a 1 micron layer of low stress glass 60 is deposited and etched (FIG. 21) using a nozzle wall mask.
[0052] 11. As illustrated in FIG. 22, the glass is etched down to the sacrificial layer using an actuator paddle wall mask.
[0053] 12. As illustrated in FIG. 23, a 5 micron layer of sacrificial material 62 is deposited and planarized using CMP.
[0054] 13. As illustrated in FIG. 24, a 3 micron layer of low stress glass 63 is deposited and etched using a nozzle rim mask.
[0055] 14. As illustrated in FIG. 25, the glass is etched down to the sacrificial layer using nozzle mask.
[0056] 15. As illustrated in FIG. 26, the wafer can be etched from the back using a deep silicon trench etcher such as the Silicon Technology Systems deep trench etcher.
[0057] 16. Finally, as illustrated in FIG. 27, the sacrificial layers are etched away releasing the ink jet structure.
[0058] Subsequently, the print head can be washed, mounted on an ink chamber, relevant electrical interconnections TAB bonded and the print head tested.
[0059] Turning now to FIG. 28, there is illustrated a portion 80 of a full colour printhead which is divided into three series of nozzles 71, 72 and 73. Each series can supply a separate color via means of a corresponding ink supply channel. Each series is further subdivided into two subrows e.g. 76, 77 with the relevant nozzles of each subrow being fired simultaneously with one subrow being fired a predetermined time after a second subrow such that a line of ink drops is formed on a page.
[0060] As illustrated in FIG. 28 the actuators a formed in a curved relationship with respect to the main nozzle access so as to provide for a more compact packing of the nozzles. Further, the block portion (21 of FIG. 6) is formed in the wall of an adjacent series with the block portion of the row 73 being formed in a separate guide rail 80 provided as an abutment surface for the TAB strip when it is abutted against the guide rail 80 so as to provide for an accurate registration of the tab strip with respect to the bond pads 81, 82 which are provided along the length of the printhead so as to provide for low impedance driving of the actuators.
[0061] The principles of the preferred embodiment can obviously be readily extended to other structures. For example, a fulcrum arrangement could be constructed which includes two arms which are pivoted around a thinned wall by means of their attachment to a cross bar. Each arm could be attached to the central cross bar by means of similarly leafed portions to that shown in FIG. 6 and FIG. 7. The distance between a first arm and the thinned wall can be L units whereas the distance between the second arm and wall can be NL units. Hence, when a translational movement is applied to the second arm for a distance of N×X units the first arm undergoes a corresponding movement of X units. The leafed portions allow for flexible movement of the arms whilest providing for full pulling strength when required.
[0062] It would be evident to those skilled in the art that the present invention can further be utilized in either mechanical arrangements requiring the application forces to enduce movement in a structure.
[0063] One form of detailed manufacturing process which can be used to fabricate monolithic ink jet print heads operating in accordance with the principles taught by the present embodiment can proceed utilizing the following steps:
[0064] 1. Using a double sided polished wafer, complete drive transistors, data distribution, and timing circuits using a 0.5 micron, one poly, 2 metal CMOS process. Relevant features of the wafer at this step are shown in FIG. 30. For clarity, these diagrams may not be to scale, and may not represent a cross section though any single plane of the nozzle. FIG. 29 is a key to representations of various materials in these manufacturing diagrams, and those of other cross referenced ink jet configurations.
[0065] 2. Etch oxide down to silicon or aluminum using Mask 1. This mask defines the ink inlet, the heater contact vias, and the edges of the print head chips. This step is shown in FIG. 31.
[0066] 3. Etch exposed silicon to a depth of 20 microns. This step is shown in FIG. 32.
[0067] 4. Deposit a 1 micron conformal layer of a first sacrificial material.
[0068] 5. Deposit 20 microns of a second sacrificial material, and planarize down to the first sacrificial layer using CMP. This step is shown in FIG. 33.
[0069] 6. Etch the first sacrificial layer using Mask 2, defining the nozzle chamber wall, the paddle, and the actuator anchor point. This step is shown in FIG. 34.
[0070] 7. Etch the second sacrificial layer down to the first sacrificial layer using Mask 3. This mask defines the paddle. This step is shown in FIG. 35.
[0071] 8. Deposit a 1 micron conformal layer of PECVD glass.
[0072] 9. Etch the glass using Mask 4, which defines the lower layer of the actuator loop.
[0073] 10. Deposit 1 micron of heater material, for example titanium nitride (TiN) or titanium diboride (TiB2). Planarize using CMP. This step is shown in FIG. 36.
[0074] 11. Deposit 0.1 micron of silicon nitride.
[0075] 12. Deposit 1 micron of PECVD glass.
[0076] 13. Etch the glass using Mask 5, which defines the upper layer of the actuator loop.
[0077] 14. Etch the silicon nitride using Mask 6, which defines the vias connecting the upper layer of the actuator loop to the lower layer of the actuator loop.
[0078] 15. Deposit 1 micron of the same heater material previously deposited. Planarize using CMP. This step is shown in FIG. 37.
[0079] 16. Deposit 1 micron of PECVD glass.
[0080] 17. Etch the glass down to the sacrificial layer using Mask 6. This mask defines the actuator and the nozzle chamber wall, with the exception of the nozzle chamber actuator slot. This step is shown in FIG. 38.
[0081] 18. Wafer probe. All electrical connections are complete at this point, bond pads are accessible, and the chips are not yet separated.
[0082] 19. Deposit 4 microns of sacrificial material and planarize down to glass using CMP.
[0083] 20. Deposit 3 microns of PECVD glass. This step is shown in FIG. 39.
[0084] 21. Etch to a depth of (approx.) 1 micron using Mask 7. This mask defines the nozzle rim. This step is shown in FIG. 40.
[0085] 22. Etch down to the sacrificial layer using Mask 8. This mask defines the roof of the nozzle chamber, and the nozzle itself. This step is shown in FIG. 41.
[0086] 23. Back-etch completely through the silicon wafer (with, for example, an ASE Advanced Silicon Etcher from Surface Technology Systems) using Mask 9. This mask defines the ink inlets which are etched through the wafer. The wafer is also diced by this etch. This step is shown in FIG. 42.
[0087] 24. Etch both types of sacrificial material. The nozzle chambers are cleared, the actuators freed, and the chips are separated by this etch. This step is shown in FIG. 43.
[0088] 25. Mount the print heads in their packaging, which may be a molded plastic former incorporating ink channels which supply the appropriate color ink to the ink inlets at the back of the wafer.
[0089] 26. Connect the print heads to their interconnect systems. For a low profile connection with minimum disruption of airflow, TAB may be used. Wire bonding may also be used if the printer is to be operated with sufficient clearance to the paper.
[0090] 27. Hydrophobize the front surface of the print heads.
[0091] 28. Fill the completed print heads with ink and test them. A filled nozzle is shown in FIG. 44.
[0092] The presently disclosed ink jet printing technology is potentially suited to a wide range of printing system including: colour and monochrome office printers, short run digital printers, high speed digital printers, offset press supplemental printers, low cost scanning printers high speed pagewidth printers, notebook computers with inbuilt pagewidth printers, portable colour and monochrome printers, colour and monochrome copiers, colour and monochrome facsimile machines, combined printer, facsimile and copying machines, label printers, large format plotters, photograph copiers, printers for digital photographic “minilabs”, video printers, PhotoCD printers, portable printers for PDAs, wallpaper printers, indoor sign printers, billboard printers, fabric printers, camera printers and fault tolerant commercial printer arrays.
[0093] It would be appreciated by a person skilled in the art that numerous variations and/or modifications may be made to the present invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects to be illustrative and not restrictive.
Ink Jet Technologies
[0094] The embodiments of the invention use an ink jet printer type device. Of course many different devices could be used. However presently popular ink jet printing technologies are unlikely to be suitable.
[0095] The most significant problem with thermal inkjet is power consumption. This is approximately 100 times that required for high speed, and stems from the energy-inefficient means of drop ejection. This involves the rapid boiling of water to produce a vapor bubble which expels the ink. Water has a very high heat capacity, and must be superheated in thermal inkjet applications. This leads to an efficiency of around 0.02%, from electricity input to drop momentum (and increased surface area) out.
[0096] The most significant problem with piezoelectric inkjet is size and cost. Piezoelectric crystals have a very small deflection at reasonable drive voltages, and therefore require a large area for each nozzle. Also, each piezoelectric actuator must be connected to its drive circuit on a separate substrate. This is not a significant problem at the current limit of around 300 nozzles per print head, but is a major impediment to the fabrication of pagewide print heads with 19,200 nozzles.
[0097] Ideally, the inkjet technologies used meet the stringent requirements of in-camera digital color printing and other high quality, high speed, low cost printing applications. To meet the requirements of digital photography, new inkjet technologies have been created. The target features include:
[0098] low power (less than 10 Watts)
[0099] high resolution capability (1,600 dpi or more)
[0100] photographic quality output
[0101] low manufacturing cost
[0102] small size (pagewidth times minimum cross section)
[0103] high speed (<2 seconds per page).
[0104] All of these features can be met or exceeded by the inkjet systems described below with differing levels of difficulty. 45 different inkjet technologies have been developed by the Assignee to give a wide range of choices for high volume manufacture. These technologies form part of separate applications assigned to the present Assignee as set out in the table below.
[0105] The inkjet designs shown here are suitable for a wide range of digital printing systems, from battery powered one-time use digital cameras, through to desktop and network printers, and through to commercial printing systems
[0106] For ease of manufacture using standard process equipment, the print head is designed to be a monolithic 0.5 micron CMOS chip with MEMS post processing. For color photographic applications, the print head is 100 mm long, with a width which depends upon the inkjet type. The smallest print head designed is IJ38, which is 0.35 mm wide, giving a chip area of 35 square mm. The print heads each contain 19,200 nozzles plus data and control circuitry.
[0107] Ink is supplied to the back of the print head by injection molded plastic ink channels. The molding requires 50 micron features, which can be created using a lithographically micromachined insert in a standard injection molding tool. Ink flows through holes etched through the wafer to the nozzle chambers fabricated on the front surface of the wafer. The print head is connected to the camera circuitry by tape automated bonding.
CROSS-REFERENCED APPLICATIONS
[0108] The following table is a guide to cross-referenced patent applications filed concurrently herewith and discussed hereinafter with the reference being utilized in subsequent tables when referring to a particular case:
Tables of Drop-on-Demand Inkjets
[0109] Eleven important characteristics of the fundamental operation of individual inkjet nozzles have been identified. These characteristics are largely orthogonal, and so can be elucidated as an eleven dimensional matrix. Most of the eleven axes of this matrix include entries developed by the present assignee.
[0110] The following tables form the axes of an eleven dimensional table of inkjet types.
[0111] Actuator mechanism (18 types)
[0112] Basic operation mode (7 types)
[0113] Auxiliary mechanism (8 types)
[0114] Actuator amplification or modification method (17 types)
[0115] Actuator motion (19 types)
[0116] Nozzle refill method (4 types)
[0117] Method of restricting back-flow through inlet (10 types)
[0118] Nozzle clearing method (9 types)
[0119] Nozzle plate construction (9 types)
[0120] Drop ejection direction (5 types)
[0121] Ink type (7 types)
[0122] The complete eleven dimensional table represented by these axes contains 36.9 billion possible configurations of inkjet nozzle. While not all of the possible combinations result in a viable inkjet technology, many million configurations are viable. It is clearly impractical to elucidate all of the possible configurations. Instead, certain inkjet types have been investigated in detail. These are designated IJ01 to IJ45 above.
[0123] Other inkjet configurations can readily be derived from these 45 examples by substituting alternative configurations along one or more of the 11 axes. Most of the IJ01 to IJ45 examples can be made into inkjet print heads with characteristics superior to any currently available inkjet technology.
[0124] Where there are prior art examples known to the inventor, one or more of these examples are listed in the examples column of the tables below. The IJ01 to IJ45 series are also listed in the examples column. In some cases, a printer may be listed more than once in a table, where it shares characteristics with more than one entry.
[0125] Suitable applications include: Home printers, Office network printers, Short run digital printers, Commercial print systems, Fabric printers, Pocket printers, Internet WWW printers, Video printers, Medical imaging, Wide format printers, Notebook PC printers, Fax machines, Industrial printing systems, Photocopiers, Photographic minilabs etc.
[0126] The information associated with the aforementioned 11 dimensional matrix are set out in the following tables.
Ink Jet Printing
[0127] A large number of new forms of ink jet printers have been developed to facilitate alternative ink jet technologies for the image processing and data distribution system. Various combinations of ink jet devices can be included in printer devices incorporated as part of the present invention. Australian Provisional Patent Applications relating to these ink jets which are specifically incorporated by cross reference include:
Ink Jet Manufacturing
[0128] Further, the present application may utilize advanced semiconductor fabrication techniques in the construction of large arrays of ink jet printers. Suitable manufacturing techniques are described in the following Australian provisional patent specifications incorporated here by cross-reference:
Fluid Supply
[0129] Further, the present application may utilize an ink delivery system to the ink jet head. Delivery systems relating to the supply of ink to a series of ink jet nozzles are described in the following Australian provisional patent specifications, the disclosure of which are hereby incorporated by cross-reference:
MEMS Technology
[0130] Further, the present application may utilize advanced semiconductor microelectromechanical techniques in the construction of large arrays of ink jet printers. Suitable microelectromechanical techniques are described in the following Australian provisional patent specifications incorporated here by cross-reference:
IR Technologies
[0131] Further, the present application may include the utilization of a disposable camera system such as those described in the following Australian provisional patent specifications incorporated here by cross-reference:
DotCard Technologies
[0132] Further, the present application may include the utilization of a data distribution system such as that described in the following Australian provisional patent specifications incorporated here by cross-reference:
Artcam Technologies
[0133] Further, the present application may include the utilization of camera and data processing techniques such as an Artcam type device as described in the following Australian provisional patent specifications incorporated here by cross-reference:
Claims
Post-issuance certificates present
The text shown below may not reflect later post-issuance changes.
I claim:
1. An apparatus for ejecting fluids from a nozzle chamber comprising:
a nozzle chamber having at least two fluid ejection apertures defined in the walls of said chamber;
a moveable paddle vane located between said fluid ejection apertures;
an actuator mechanism attached to said moveable paddle vane and adapted to move said paddle vane in a first direction so as to cause the ejection of fluid drops out of a first fluid ejection aperture and to further move said paddle vane in a second alternative direction so as to cause the ejection of fluid drops out of a second fluid ejection aperture.
2. An apparatus as claimed in claim 1 wherein said actuator comprises a thermal actuator having at least two heater elements with a first of said elements being actuated to cause said paddle vane to move in a first direction and a second heater element being actuated to cause said paddle vane to move in a second direction.
3. An apparatus as claimed in claim 2 wherein said heater elements have a high bend efficiency wherein said bend efficiency is defined as the youngs modulus times the coefficient of thermal expansion divided by the density and by the specific heat capacity.
4. An apparatus as claimed in claim 2 wherein said heater elements are arranged on opposite sides of a central arm, said central arm having a low thermal conductivity.
5. An apparatus as claimed in claim 4 wherein said central arm comprises substantially glass.
6. An apparatus as claimed in claim 2 wherein said paddle vane and said actuator are joined at a fulcrum pivot point, said fulcrum pivot point comprising a thinned portion of said nozzle chamber wall.
7. An apparatus as claimed in claim 1 wherein said actuator includes one end fixed to a substrate and a second end containing a bifurcated tongue having two leaf portions on each end of said bifurcated tongue said leaf portions interconnecting to a corresponding side of said paddle with said tongue such that, upon actuation of said actuator, one of said leaf portions pulls on said paddle end.
8. An apparatus as claimed in claim 1 further comprising:
a fluid supply channel connecting said nozzle chamber with a fluid supply for supplying fluid to said nozzle chamber said connection being in a wall of said chamber substantially adjacent the quiescent position of said paddle vane.
9. An apparatus as claimed in claim 8 wherein said connection comprises a slot defined in the wall of said chamber, said slot having similar dimensions to a cross-sectional profile of said paddle vane.
10. An apparatus as claimed in claim 1 wherein said fluid ejection apertures include a rim defined around an outer surface thereof.
11. A multiplicity of apparatuses as claimed in claim 1 wherein said fluid ejection apertures are grouped together spatially into spaced apart rows and fluid is ejected from the fluid ejection apertures of each of said rows in phases.
12. A multiplicity of apparatuses as claimed in claim 11 wherein said apparatuses are utilized for ink jet printing.
13. A multiplicity of apparatuses as claimed in claim 12 said nozzle chambers are further grouped into multiple ink colors and with each of said nozzles being supplied with a corresponding ink color.
14. A method of ejecting drops of fluid from a nozzle chamber having at least two nozzle apertures defined in the wall of said nozzle chambers utilizing a moveable paddle vane attached to an actuator mechanism, said method comprising the steps of:
actuating said actuator to cause said moveable paddle to move in a first direction so as to eject drops from a first of said nozzle apertures; and
actuating said actuator to cause said moveable paddle to move in a second direction so as to eject drops from a second of said nozzle apertures.
15. A method as claimed in claim 14 wherein an array of nozzle chambers are arranged in a pagewidth print head and the moveable paddles of each nozzle chamber are driven in phase.
Patent Citations (1)
| Patent | Date | Inventor | Cited By |
|---|---|---|---|
| JP404001051 | 1992-01-01 | Examiner |