Source: http://www.patentsencyclopedia.com/app/20080309727
Timestamp: 2018-05-25 19:30:48
Document Index: 735126342

Matched Legal Cases: ['ART01', 'ART02', 'ART03', 'ART04', 'ART06', 'ART07', 'ART08', 'ART09', 'ART10', 'ART11', 'ART12', 'ART13', 'ART15', 'ART16', 'ART17', 'ART18', 'ART19', 'ART20', 'ART21', 'ART22', 'ART24', 'ART25', 'ART26', 'ART27', 'ART28', 'ART29', 'ART30', 'ART31', 'ART32', 'ART33', 'ART34', 'ART38', 'ART39', 'ART42', 'ART43', 'ART44', 'ART45', 'ART46', 'ART47', 'ART48', 'ART50', 'ART51', 'ART52', 'ART53', 'ART54', 'ART56', 'ART57', 'ART58', 'ART59', 'ART60', 'ART61', 'ART62', 'ART63', 'ART64', 'ART65', 'ART66', 'ART68', 'ART69']

PRINTHEAD INTEGRATED CIRCUIT WITH INK SUPPLY FROM BACK FACE - Patent application
Patent application title: PRINTHEAD INTEGRATED CIRCUIT WITH INK SUPPLY FROM BACK FACE
Patent application number: 20080309727
PRINTHEAD INTEGRATED CIRCUIT WITH INK SUPPLY FROM BACK FACE - Patent application <?php require_once('/home/patents/php/mtc.config.php'); require_once('/home/patents/php/mtc.class.php'); $MTC = new MTC(); $MTC->init(); ?>
An inkjet printhead that has an array of droplet ejectors supported on one face of a printhead integrated circuit (IC). Each of the droplet ejectors has a nozzle aperture and an actuator for ejecting a droplet of ink through the nozzle aperture. The printhead IC having a printhead surface layer on one face which defines all the nozzle apertures on the array. The printhead IC also having a back face that is opposite said one face on which the printhead surface layer is formed, and at least one supply conduit extending from the back face to the array of droplet ejectors. The at least one supply conduit is in fluid communication with a plurality of the droplet ejectors in the array.
1. An inkjet printhead comprising:an array of droplet ejectors supported on a printhead integrated circuit (IC), each of the droplet ejectors having a nozzle aperture and an actuator for ejecting a droplet of ink through the nozzle aperture, the printhead IC having a printhead surface layer on one face, the printhead surface layer defining all the nozzle apertures on the array, the printhead IC also having a back face that is opposite said one face on which the printhead surface layer is formed, and at least one supply conduit extending from the back face to the array of droplet ejectors such that the at least one supply conduit is in fluid communication with a plurality of the droplet ejectors in the array.
2. An inkjet printhead according to claim 1 wherein the printhead IC has a plurality of the supply conduits and drive circuitry for providing the actuators with power, the drive circuitry having patterned layers of metal separated by interleaved layers of dielectric material, the layers of metal being interconnected by conductive vias, wherein the drive circuitry extends between the plurality of supply conduits.
3. An inkjet printhead according to claim 1 wherein the metal layers are 1 micron thick.
TABLE-US-00001 CROSS-REFERENCED US PATENT/PATENT AUSTRALIAN APPLICATION (CLAIMING PROVISIONAL RIGHT OF PRIORITY PATENT FROM AUSTRALIAN DOCKET APPLICATION NO. PROVISIONAL APPLICATION) NO. PO7991 6,750,901 ART01 PO8505 6,476,863 ART02 PO7988 6,788,336 ART03 PO9395 6,322,181 ART04 PO8017 6,597,817 ART06 PO8014 6,227,648 ART07 PO8025 6,727,948 ART08 PO8032 6,690,419 ART09 PO7999 6,727,951 ART10 PO7998 09/112,742 ART11 PO8031 09/112,741 ART12 PO8030 6,196,541 ART13 PO7997 6,195,150 ART15 PO7979 6,362,868 ART16 PO8015 09/112,738 ART17 PO7978 6831681 ART18 PO7982 6,431,669 ART19 PO7989 6,362,869 ART20 PO8019 6,472,052 ART21 PO7980 6,356,715 ART22 PO8018 09/112,777 ART24 PO7938 6,636,216 ART25 PO8016 6,366,693 ART26 PO8024 6,329,990 ART27 PO7940 09/113,072 ART28 PO7939 6,459,495 ART29 PO8501 6,137,500 ART30 PO8500 6,690,416 ART31 PO7987 7,050,143 ART32 PO8022 6,398,328 ART33 PO8497 09/113,090 ART34 PO8020 6,431,704 ART38 PO8023 09/113,222 ART39 PO8504 09/112,786 ART42 PO8000 6,415,054 ART43 PO7977 09/112,782 ART44 PO7934 6,665,454 ART45 PO7990 6,542,645 ART46 PO8499 6,486,886 ART47 PO8502 6,381,361 ART48 PO7981 6,317,192 ART50 PO7986 6850274 ART51 PO7983 09/113,054 ART52 PO8026 6,646,757 ART53 PO8027 09/112,759 ART54 PO8028 6,624,848 ART56 PO9394 6,357,135 ART57 PO9396 09/113,107 ART58 PO9397 6,271,931 ART59 PO9398 6,353,772 ART60 PO9399 6,106,147 ART61 PO9400 6,665,008 ART62 PO9401 6,304,291 ART63 PO9402 09/112,788 ART64 PO9403 6,305,770 ART65 PO9405 6,289,262 ART66 PP0959 6,315,200 ART68 PP1397 6,217,165 ART69 PP2370 6,786,420 DOT01 PP2371 09/113,052 DOT02 PO8003 6,350,023 Fluid01 PO8005 6,318849 Fluid02 PO8066 6,227,652 IJ01 PO8072 6,213,588 IJ02 PO8040 6,213,589 IJ03 PO8071 6,231,163 IJ04 PO8047 6,247,795 IJ05 PO8035 6,394,581 IJ06 PO8044 6,244,691 IJ07 PO8063 6,257,704 IJ08 PO8057 6,416,168 IJ09 PO8056 6,220,694 IJ10 PO8069 6,257,705 IJ11 PO8049 6,247,794 IJ12 PO8036 6,234,610 IJ13 PO8048 6,247,793 IJ14 PO8070 6,264,306 IJ15 PO8067 6,241,342 IJ16 PO8001 6,247,792 IJ17 PO8038 6,264,307 IJ18 PO8033 6,254,220 IJ19 PO8002 6,234,611 IJ20 PO8068 6,302,528 IJ21 PO8062 6,283.582 IJ22 PO8034 6,239,821 IJ23 PO8039 6,338,547 IJ24 PO8041 6,247,796 IJ25 PO8004 6,557,977 IJ26 PO8037 6,390,603 IJ27 PO8043 6,362,843 IJ28 PO8042 6,293,653 IJ29 PO8064 6,312,107 IJ30 PO9389 6,227,653 IJ31 PO9391 6,234,609 IJ32 PP0888 6,238,040 IJ33 PP0891 6,188,415 IJ34 PP0890 6,227,654 IJ35 PP0873 6,209,989 IJ36 PP0993 6,247,791 IJ37 PP0890 6,336,710 IJ38 PP1398 6,217,153 IJ39 PP2592 6,416,167 IJ40 PP2593 6,243,113 IJ41 PP3991 6,283,581 IJ42 PP3987 6,247,790 IJ43 PP3985 6,260,953 IJ44 PP3983 6,267,469 IJ45 PO7935 6,224,780 IJM01 PO7936 6,235,212 IJM02 PO7937 6,280,643 IJM03 PO8061 6,284,147 IJM04 PO8054 6,214,244 IJM05 PO8065 6,071,750 IJM06 PO8055 6,267,905 IJM07 PO8053 6,251,298 IJM08 PO8078 6,258,285 IJM09 PO7933 6,225,138 IJM10 PO7950 6,241,904 IJM11 PO7949 6,299,786 IJM12 PO8060 09/113,124 IJM13 PO8059 6,231,773 IJM14 PO8073 6,190,931 IJM15 PO8076 6,248,249 IJM16 PO8075 6,290,862 IJM17 PO8079 6,241,906 IJM18 PO8050 6,565,762 IJM19 PO8052 6,241,905 IJM20 PO7948 6,451,216 IJM21 PO7951 6,231,772 IJM22 PO8074 6,274,056 IJM23 PO7941 6,290,861 IJM24 PO8077 6,248,248 IJM25 PO8058 6,306,671 IJM26 PO8051 6,331,258 IJM27 PO8045 6,111,754 IJM28 PO7952 6,294,101 IJM29 PO8046 6,416,679 IJM30 PO9390 6,264,849 IJM31 PO9392 6,254,793 IJM32 PP0889 6,235,211 IJM35 PP0887 6,491,833 IJM36 PP0882 6,264,850 IJM37 PP0874 6,258,284 IJM38 PP1396 6,312,615 IJM39 PP3989 6,228,668 IJM40 PP2591 6,180,427 IJM41 PP3990 6,171,875 IJM42 PP3986 6,267,904 IJM43 PP3984 6,245,247 IJM44 PP3982 6,315,914 IJM45 PP0895 6,231,148 IR01 PP0870 09/113,106 IR02 PP0869 6,293,658 IR04 PP0887 6,614,560 IR05 PP0885 6,238,033 IR06 PP0884 6,312,070 IR10 PP0886 6,238,111 IR12 PP0871 09/113,086 IR13 PP0876 09/113,094 IR14 PP0877 6,378,970 IR16 PP0878 6,196,739 IR17 PP0879 09/112,774 IR18 PP0883 6,270,182 IR19 PP0880 6,152,619 IR20 PP0881 09/113,092 IR21 PO8006 6,087,638 MEMS02 PO8007 6,340,222 MEMS03 PO8008 09/113,062 MEMS04 PO8010 6,041,600 MEMS05 PO8011 6,299,300 MEMS06 PO7947 6,067,797 MEMS07 PO7944 6,286,935 MEMS09 PO7946 6,044,646 MEMS10 PO9393 09/113,065 MEMS11 PP0875 09/113,078 MEMS12 PP0894 6,382,769 MEMS13
TABLE-US-00002 IJ96US IJ97US IJ98US IJ99US IJ100US IJ101US IJ102US IJ103US IJ104US IJ105US IJ106US IJ107US IJ108US IJ109US IJ110US
[0016]Given these limits on nozzle array size, pagewidth printheads using this two-part design are impractical. A stationary printhead extending the printing width of the media substrate would require many separate printhead arrays mounted in precise alignment with each other. The complexity of this arrangement makes such printers commercially unrealistic.
[0019]an array of droplet ejectors supported on a printhead integrated circuit (IC), each of the droplet ejectors having a nozzle aperture and an actuator for ejecting a droplet of ink through the nozzle aperture, the printhead IC having a printhead surface layer on one face, the printhead surface layer defining all the nozzle apertures on the array, the printhead IC also having a back face that is opposite said one face on which the printhead surface layer is formed, and at least one supply conduit extending from the back face to the array of droplet ejectors such that the at least one supply conduit is in fluid communication with a plurality of the droplet ejectors in the array.
[0020]Supplying the array of droplet ejectors with ink from the back face of the printhead IC instead of along the front face provides more room to the electrical contacts and drive circuitry. This in turn, provides the scope to increase the density of droplet ejectors per unit area on the printhead IC.
[0021]Preferably, the printhead IC has a plurality of the supply conduits and drive circuitry for providing the actuators with power, the drive circuitry having patterned layers of metal separated by interleaved layers of dielectric material, the layers of metal being interconnected by conductive vias, wherein the drive circuitry extends between the plurality of supply conduits.
[0022]In a further preferred form, the array has a nozzle aperture density of more than 100 nozzle apertures per square millimetre and all the nozzle apertures are formed in of the printhead IC.
[0023]Preferably, the array of droplet ejectors is arranged as a plurality of rows of the droplet ejectors, the printhead IC further comprises an ink supply channel extending parallel to the plurality of rows, such that the ink supply channel connects to the plurality of supply conduits extending from the back face of the printhead IC. Preferably, the supply channel extends between at least two of the plurality of rows. In a particularly preferred form, the printhead IC has an elongate configuration with its longitudinal extent parallel to the rows of droplet ejectors, the printhead IC further comprising a series of electrical contacts along of its longitudinal sides for receiving power and print data for all the droplet ejectors in the array.
[0024]Preferably, each of the metal layers are less than 2 microns thick.
[0025]Incorporating the drive circuitry and the droplet ejectors onto the same supporting substrate reduces the number of electrical connections needed on the printhead IC and the resistive losses when transmitting power to the actuators. The circuitry on the printhead IC needs to have more than just power and ground metal layers in order to provide the necessary drive FETs, shift registers and so on. However, each metal layer can be thinner and fabricated using well known and efficient techniques employed in standard semiconductor fabrication. Overall, this yields production efficiencies in time and cost.
[0026]Preferably, the metal layers are each less than 1 micron thick. In a still further preferred form, the metal layers are 0.5 microns thick. Half micron CMOS is often used in semiconductor fabrication and is thick enough to ensure that the connections at the bond pads are reliable.
[0027]Preferably, the array has a nozzle aperture density of more than 100 nozzle apertures per square millimetre. Preferably, the array has a nozzle aperture density of more than 200 nozzle apertures per square millimetre. In a further preferred form, the array has a nozzle aperture density of more than 300 nozzle apertures per square millimetre.
[0028]Forming the nozzle apertures within a layer on one side of the underlying wafer instead of laser ablating nozzles in a separated plate that is subsequently mounted to the printhead integrated circuit significantly improves the accuracy of registration between an actuator and its corresponding nozzle. With more precise registration between the nozzle aperture and the actuator, a greater nozzle density is possible. Nozzle density has a direct bearing on the print resolution and or print speeds. A high density array of nozzles can print to all the addressable locations (the grid of locations on the media substrate at which the printer can print a dot) with less passes of the printhead or ideally, a single pass.
[0029]In some embodiments, the array has more than 2000 droplet ejectors. Preferably, the array has more than 10,000 droplet ejectors. In a further preferred form, the array has more than 15,000 droplet ejectors. Increasing the number of nozzles fabricated on a single printhead IC allows larger arrays, faster print speeds and ultimately pagewidth printheads.
[0030]Preferably, the printhead surface layer is less than 10 microns thick. In a further preferred form, the printhead surface layer is less than 8 microns thick. In a still further preferred form, the printhead surface layer is less than 5 microns thick. In particular embodiments, the printhead surface layer is between 1.5 microns and 3.0 microns.
[0031]Forming the nozzle apertures in a thin surface layer reduces stresses caused by differential thermal expansion. Thin surface layers mean that the `barrel` of the nozzle aperture is short and has less fluidic drag on the droplets as they are ejected. This reduces the ejection energy that the actuator needs to impart to the ink which in turn reduces the energy needed to be input into the actuator. With the actuators operating at lower power, they can be placed closer together on the printhead IC because there is less cross talk between nozzles and less excess heat generated. The close spacing increases the density of droplet ejectors within the array.
[0032]Preferably, each of the droplet ejectors in the array is configured to eject droplets with a volume less than 3 pico-litres each. In a further preferred form, each of the droplet ejectors in the array is configured to eject droplets with a volume less than 2 pico-litres each. In a particularly preferred form, the droplets ejected have a volume between 1 pico-litre and 2 pico-litres.
[0033]Configuring the ejector so that it ejects small volume drops reduces the energy needed to eject drops.
[0034]Preferably, the actuator in each of the droplet ejectors is configured to generate a pressure pulse in a quantity of ink adjacent the nozzle aperture, the pressure pulse being directed towards the nozzles aperture such that the droplet of ink is ejected through the nozzle aperture, the actuator being positioned in the droplet ejector such that it is less than 30 microns from an exterior surface of the printhead surface layer. Preferably, the actuator is positioned in the droplet ejector such that it is less than 20 microns from an exterior surface of the printhead surface layer. In a further preferred form, the actuator being positioned in the droplet ejector such that it is less than 15 microns from an exterior surface of the printhead surface layer.
[0035]In some preferred embodiments, the nozzle apertures each have an area less than 600 microns squared. In a further preferred form, the nozzle apertures each have an area less than 400 microns squared. In a particularly preferred form, the nozzle apertures each have an area between 150 microns squared and 200 microns squared.
[0036]Preferably, during printing 100% coverage at full print rate, each of the actuators has an average power consumption less than 1.5 mW. In a further preferred form, the average power consumption is between 0.5 mW and 1.0 mW. In a still further preferred form, the array has more than 15,000 of the droplet ejectors and operates at less than 10 Watts during printing 100% coverage at full print rate.
[0037]Preferably, each of the actuators is configured to consume less than 1 Watt during activation. In a further preferred form, each of the actuators is configured to consume less than 500 mW during activation. In some embodiments, each of the actuators is configured to consume between 100 mW and 500 mW during activation.
[0038]Preferably, each of the droplet ejectors has a chamber in which the actuator is positioned, the chamber having an inlet for fluid communication with an ink supply, and a filter structure in the inlet to inhibit ingress of contaminants and air bubbles into the chamber. In a particularly preferred form, the filter structure is a plurality of spaced columns. In some embodiments, the spaced columns each extend generally parallel to the droplet ejection direction. A filter structure at the inlet to each ink chamber is more likely to remove contaminants than a filter positioned further upstream in the in the ink supply flow. Contaminants, including air bubbles, can originate at all points along the ink supply line, so there is less chance of nozzle clogging or other detrimental effects if the ink flow is filtered at each of the chamber inlets.
[0039]Preferably, the array of droplet ejectors is arranged as a plurality of rows of the droplet ejectors, the inkjet printhead further comprising an ink supply channel extending parallel to the plurality of rows, and an inlet conduit extending from the supply channel to an opposing surface of the printhead IC. Preferably, the supply channel extends between at least two of the plurality of rows. Feeding ink to the rows of droplet ejectors via a parallel supply channel that has a supply conduit to the `back` of the IC, reduces the number of deep anisotropic back etches. Less back etching preserves the structural integrity of the printhead IC which is more robust and less likely to be damaged by die handling equipment.
[0040]Preferably, the droplet ejectors are configured to eject ink droplets at a velocity less than 4.5 m/s. In a further preferred form, the velocity is less than 4.0 m/s. The Applicant's work has found drop ejection velocities greater than 4.5 m/s have significantly more satellite drops. Furthermore, tests show a velocity less than 4.0 m/s have negligible satellite drops.
[0041]Preferably, each of the droplet ejectors has a chamber in which the actuator is positioned, the chamber having a volume less than 30,000 microns cubed. In a further preferred form, the volume is less than 25,000 microns cubed. Low energy ejection of ink droplets generates little, if any, excess heat in the printhead. A build up of excess heat in the printhead imposes a limit on the nozzle firing frequency and thereby limits the print speed. The IJ30 printhead is self cooling (the heat generated by the thermal actuator is removed from the printhead with the ejected drop). In this case, the print speed is only limited by the rate at which the ink can be supplied to the printhead or the speed that the media substrate can be fed past the printhead. Reducing the volume of the ink chambers reduces the volume of ink in which the heat can dissipate. However, a reduced volume ink chamber has a fast refill time and relies solely on capillary action. As the actuator is configured for low energy input, the reduced volume of ink does not cause problems for heat dissipation.
[0064]FIG. 4 provides a legend of the materials indicated in FIG. 5 to 15;
TABLE-US-00003 ACTUATOR MECHANISM (APPLIED ONLY TO SELECTED INK DROPS) Description Advantages Disadvantages Examples Thermal An electrothermal Large force High power Canon Bubblejet bubble heater heats the ink to generated Ink carrier 1979 Endo et al GB above boiling point, Simple limited to water patent 2,007,162 transferring significant construction Low efficiency Xerox heater-in- heat to the aqueous No moving parts High pit 1990 Hawkins et ink. A bubble Fast operation temperatures al U.S. Pat. No. 4,899,181 nucleates and quickly Small chip area required Hewlett-Packard forms, expelling the required for actuator High mechanical TIJ 1982 Vaught et ink. stress al U.S. Pat. No. 4,490,728 The efficiency of the Unusual process is low, with materials required typically less than Large drive 0.05% of the electrical transistors energy being Cavitation causes transformed into actuator failure kinetic energy of the Kogation reduces drop. bubble formation Large print heads are difficult to fabricate Piezoelectric A piezoelectric crystal Low power Very large area Kyser et al U.S. Pat. No. such as lead consumption required for actuator 3,946,398 lanthanum zirconate Many ink types Difficult to Zoltan U.S. Pat. No. (PZT) is electrically can be used integrate with 3,683,212 activated, and either Fast operation electronics 1973 Stemme expands, shears, or High efficiency High voltage U.S. Pat. No. 3,747,120 bends to apply drive transistors Epson Stylus pressure to the ink, required Tektronix ejecting drops. Full pagewidth IJ04 print heads impractical due to actuator size Requires electrical poling in high field strengths during manufacture Electro- An electric field is Low power Low maximum Seiko Epson, strictive used to activate consumption strain (approx. Usui et all JP electrostriction in Many ink types 0.01%) 253401/96 relaxor materials such can be used Large area IJ04 as lead lanthanum Low thermal required for actuator zirconate titanate expansion due to low strain (PLZT) or lead Electric field Response speed magnesium niobate strength required is marginal (~10 μs) (PMN). (approx. 3.5 V/μm) High voltage can be generated drive transistors without difficulty required Does not require Full pagewidth electrical poling print heads impractical due to actuator size Ferroelectric An electric field is Low power Difficult to IJ04 used to induce a phase consumption integrate with transition between the Many ink types electronics antiferroelectric (AFE) can be used Unusual and ferroelectric (FE) Fast operation materials such as phase. Perovskite (<1 μs) PLZSnT are materials such as tin Relatively high required modified lead longitudinal strain Actuators require lanthanum zirconate High efficiency a large area titanate (PLZSnT) Electric field exhibit large strains of strength of around 3 V/μm up to 1% associated can be readily with the AFE to FE provided phase transition. Electrostatic Conductive plates are Low power Difficult to IJ02, IJ04 plates separated by a consumption operate electrostatic compressible or fluid Many ink types devices in an dielectric (usually air). can be used aqueous Upon application of a Fast operation environment voltage, the plates The electrostatic attract each other and actuator will displace ink, causing normally need to be drop ejection. The separated from the conductive plates may ink be in a comb or Very large area honeycomb structure, required to achieve or stacked to increase high forces the surface area and High voltage therefore the force. drive transistors may be required Full pagewidth print heads are not competitive due to actuator size Electrostatic A strong electric field Low current High voltage 1989 Saito et al, pull is applied to the ink, consumption required U.S. Pat. No. 4,799,068 on ink whereupon Low temperature May be damaged 1989 Miura et al, electrostatic attraction by sparks due to air U.S. Pat. No. 4,810,954 accelerates the ink breakdown Tone-jet towards the print Required field medium. strength increases as the drop size decreases High voltage drive transistors required Electrostatic field attracts dust Permanent An electromagnet Low power Complex IJ07, IJ10 magnet directly attracts a consumption fabrication electro- permanent magnet, Many ink types Permanent magnetic displacing ink and can be used magnetic material causing drop ejection. Fast operation such as Neodymium Rare earth magnets High efficiency Iron Boron (NdFeB) with a field strength Easy extension required. around 1 Tesla can be from single nozzles High local used. Examples are: to pagewidth print currents required Samarium Cobalt heads Copper (SaCo) and magnetic metalization should materials in the be used for long neodymium iron boron electromigration family (NdFeB, lifetime and low NdDyFeBNb, resistivity NdDyFeB, etc) Pigmented inks are usually infeasible Operating temperature limited to the Curie temperature (around 540 K) Soft A solenoid induced a Low power Complex IJ01, IJ05, IJ08, magnetic magnetic field in a soft consumption fabrication IJ10, IJ12, IJ14, core electro- magnetic core or yoke Many ink types Materials not IJ15, IJ17 magnetic fabricated from a can be used usually present in a ferrous material such Fast operation CMOS fab such as as electroplated iron High efficiency NiFe, CoNiFe, or alloys such as CoNiFe Easy extension CoFe are required [1], CoFe, or NiFe from single nozzles High local alloys. Typically, the to pagewidth print currents required soft magnetic material heads Copper is in two parts, which metalization should are normally held be used for long apart by a spring. electromigration When the solenoid is lifetime and low actuated, the two parts resistivity attract, displacing the Electroplating is ink. required High saturation flux density is required (2.0-2.1 T is achievable with CoNiFe [1]) Lorenz The Lorenz force Low power Force acts as a IJ06, IJ11, IJ13, force acting on a current consumption twisting motion IJ16 carrying wire in a Many ink types Typically, only a magnetic field is can be used quarter of the utilized. Fast operation solenoid length This allows the High efficiency provides force in a magnetic field to be Easy extension useful direction supplied externally to from single nozzles High local the print head, for to pagewidth print currents required example with rare heads Copper earth permanent metalization should magnets. be used for long Only the current electromigration carrying wire need be lifetime and low fabricated on the print- resistivity head, simplifying Pigmented inks materials are usually requirements. infeasible Magneto- The actuator uses the Many ink types Force acts as a Fischenbeck, striction giant magnetostrictive can be used twisting motion U.S. Pat. No. 4,032,929 effect of materials Fast operation Unusual IJ25 such as Terfenol-D (an Easy extension materials such as alloy of terbium, from single nozzles Terfenol-D are dysprosium and iron to pagewidth print required developed at the Naval heads High local Ordnance Laboratory, High force is currents required hence Ter-Fe-NOL). available Copper For best efficiency, the metalization should actuator should be pre- be used for long stressed to approx. 8 MPa. electromigration lifetime and low resistivity Pre-stressing may be required Surface Ink under positive Low power Requires Silverbrook, EP tension pressure is held in a consumption supplementary force 0771 658 A2 and reduction nozzle by surface Simple to effect drop related patent tension. The surface construction separation applications tension of the ink is No unusual Requires special reduced below the materials required in ink surfactants bubble threshold, fabrication Speed may be causing the ink to High efficiency limited by surfactant egress from the Easy extension properties nozzle. from single nozzles to pagewidth print heads Viscosity The ink viscosity is Simple Requires Silverbrook, EP reduction locally reduced to construction supplementary force 0771 658 A2 and select which drops are No unusual to effect drop related patent to be ejected. A materials required in separation applications viscosity reduction can fabrication Requires special be achieved Easy extension ink viscosity electrothermally with from single nozzles properties most inks, but special to pagewidth print High speed is inks can be engineered heads difficult to achieve for a 100:1 viscosity Requires reduction. oscillating ink pressure A high temperature difference (typically 80 degrees) is required Acoustic An acoustic wave is Can operate Complex drive 1993 Hadimioglu generated and without a nozzle circuitry et al, EUP 550,192 focussed upon the plate Complex 1993 Elrod et al, drop ejection region. fabrication EUP 572,220 Low efficiency Poor control of drop position Poor control of drop volume Thermo- An actuator which Low power Efficient aqueous IJ03, IJ09, IJ17, elastic bend relies upon differential consumption operation requires a IJ18, IJ19, IJ20, actuator thermal expansion Many ink types thermal insulator on IJ21, IJ22, IJ23, upon Joule heating is can be used the hot side IJ24, IJ27, IJ28, used. Simple planar Corrosion IJ29, IJ30, IJ31, fabrication prevention can be IJ32, IJ33, IJ34, Small chip area difficult IJ35, IJ36, IJ37, required for each Pigmented inks IJ38, IJ39, IJ40, actuator may be infeasible, IJ41 Fast operation as pigment particles High efficiency may jam the bend CMOS actuator compatible voltages and currents Standard MEMS processes can be used Easy extension from single nozzles
2009-03-05 Printhead integrated circuit with multiple ink inlet flow paths
2008-12-18 Printhead integrated circuit with actuators close to exterior surface
2009-04-02 Printhead integrated circuit with vapor bubbles offset from nozzle axis