Source: http://www.patentsencyclopedia.com/app/20090096834
Timestamp: 2017-12-14 13:56:32
Document Index: 738729666

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Printhead Nozzle Arrangement With A Roof Structure Having A Nozzle Rim Supported By A Series Of Struts - Patent application
Patent application title: Printhead Nozzle Arrangement With A Roof Structure Having A Nozzle Rim Supported By A Series Of Struts
Patent application number: 20090096834
Printhead Nozzle Arrangement With A Roof Structure Having A Nozzle Rim Supported By A Series Of Struts - Patent application <?php require_once('/home/patents/php/mtc.config.php'); require_once('/home/patents/php/mtc.class.php'); $MTC = new MTC(); $MTC->init(); ?>
1. A nozzle arrangement for an inkjet printhead, the nozzle arrangement comprising a substrate with a layer of drive circuitry, the substrate defining an ink chamber with an ink supply channel etched through the substrate; anda roof structure having a roof layer over the chamber which comprises:a nozzle rim positioned about an ejection port defined in the roof layer above the chamber;a plurality of actuators radially spaced about, and displaceable with respect to, the nozzle rim, each actuator configured to thermally expand upon receiving current from the drive circuitry, said expansion moving the actuators into the chamber to increase a fluid pressure inside the chamber to eject a drop of ink via the ejection port; anda series of struts interspersed between the actuators to support the nozzle rim with respect to the roof layer.
[0001]This application is a Continuation Application of U.S. application Ser. No. 11/525,860 filed on Sep. 25, 2006, which is a Continuation Application of U.S. application Ser. No. 11/036,021 filed Jan. 18, 2005, now issued as U.S. Pat. No. 7,156,495, which is a Continuation Application of U.S. application Ser. No. 10/636,278 filed Aug. 8, 2003, now U.S. Pat. No. 6,886,917, which is a Continuation of U.S. Ser. No. 09/854,703 filed May 14, 2001, now U.S. Pat. No. 6,981,757, which is a continuation of U.S. application Ser. No. 09/112,806 filed Jul. 10, 1998, now U.S. Pat. No. 6,247,790 all of which are herein incorporated by reference.
TABLE-US-00001 US PATENT/PATENT APPLICATION CROSS-REFERENCED (CLAIMING RIGHT AUSTRALIAN OF PRIORITY FROM PROVISIONAL PATENT AUSTRALIAN PROVISIONAL DOCKET APPLICATION NO. 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 PO8030 6,196,541 ART13 PO7997 6,195,150 ART15 PO7979 6,362,868 ART16 PO7978 6,831,681 ART18 PO7982 6,431,669 ART19 PO7989 6,362,869 ART20 PO8019 6,472,052 ART21 PO7980 6,356,715 ART22 PO8018 6,894,694 ART24 PO7938 6,636,216 ART25 PO8024 6,329,990 ART27 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 7,110,024 ART34 PO8020 6,431,704 ART38 PO8504 6,879,341 ART42 PO8000 6,415,054 ART43 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 6,850,274 ART51 PO7983 09/113,054 ART52 PO8026 6,646,757 ART53 PO8028 6,624,848 ART56 PO9394 6,357,135 ART57 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 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 PO8003 6,350,023 Fluid01 PO8005 6,318,849 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 6,866,789 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 6,110,754 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 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 PP0877 6,378,970 IR16 PP0878 6,196,739 IR17 PP0883 6,270,182 IR19 PP0880 6,152,619 IR20 PO8006 6,087,638 MEMS02 PO8007 6,340,222 MEMS03 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 PP0894 6,382,769 MEMS13
[0004]The present invention relates to the field of inkjet printing and, in particular, discloses an inverted radial back-curling thermoelastic ink jet printing mechanism.
[0005]Many different types of printing mechanisms have been invented, a large number of which are presently in use. The known forms of printers have a variety of methods for marking the print media with a relevant marking media.
[0006]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.
[0007]Many different techniques of 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).
[0008]Ink Jet printers themselves come in many different forms. The utilization of a continuous stream of 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 electro-static ink jet printing.
[0009]U.S. Pat. No. 3,596,275 by Sweet also discloses a process of a continuous ink jet printing including a 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).
[0010]Piezoelectric ink jet printers are also one form of commonly utilized ink jet printing device. Piezoelectric 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 form of operation of a piezoelectric crystal, Stemme in U.S. Pat. No. 3,747,120 (1972) which discloses a bend mode of piezoelectric operation, Howkins in U.S. Pat. No. 4,459,601 which discloses a piezoelectric push mode actuation of the ink jet stream and Fischbeck in U.S. Pat. No. 4,584,590 which discloses a shear mode type of piezoelectric transducer element.
[0011]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. 4,490,728. Both the aforementioned references disclose ink jet printing techniques which rely on 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.
[0012]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 and operation, durability and consumables.
[0013]In accordance with a first aspect of the present invention, there is provided a nozzle arrangement for an ink jet printhead, the arrangement comprising: a nozzle chamber defined in a wafer substrate for the storage of ink to be ejected; an ink ejection port having a rim formed on one wall of the chamber; and a series of actuators attached to the wafer substrate, and forming a portion of the wall of the nozzle chamber adjacent the rim, the actuator paddles further being actuated in unison so as to eject ink from the nozzle chamber via the ink ejection nozzle.
[0014]The actuators can include a surface which bends inwards away from the centre of the nozzle chamber upon actuation. The actuators are preferably actuated by means of a thermal actuator device. The thermal actuator device may comprise a conductive resistive heating element encased within a material having a high coefficient of thermal expansion. The element can be serpentine to allow for substantially unhindered expansion of the material. The actuators are preferably arranged radially around the nozzle rim.
[0015]The actuators can form a membrane between the nozzle chamber and an external atmosphere of the arrangement and the actuators bend away from the external atmosphere to cause an increase in pressure within the nozzle chamber thereby initiating a consequential ejection of ink from the nozzle chamber. The actuators can bend away from a central axis of the nozzle chamber.
[0016]The nozzle arrangement can be formed on the wafer substrate utilizing micro-electro mechanical techniques and further can comprise an ink supply channel in communication with the nozzle chamber. The ink supply channel may be etched through the wafer. The nozzle arrangement may include a series of struts which support the nozzle rim.
[0017]The arrangement can be formed adjacent to neighbouring arrangements so as to form a pagewidth printhead.
[0019]FIGS. 1-3 are schematic sectional views illustrating the operational principles of the preferred embodiment;
[0020]FIG. 4(a) and FIG. 4(b) are again schematic sections illustrating the operational principles of the thermal actuator device;
[0021]FIG. 5 is a side perspective view, partly in section, of a single nozzle arrangement constructed in accordance with the preferred embodiments;
[0022]FIGS. 6-13 are side perspective views, partly in section, illustrating the manufacturing steps of the preferred embodiments;
[0023]FIG. 14 illustrates an array of ink jet nozzles formed in accordance with the manufacturing procedures of the preferred embodiment;
[0024]FIG. 15 provides a legend of the materials indicated in FIGS. 16 to 23; and
[0025]FIG. 16 to FIG. 23 illustrate sectional views of the manufacturing steps in one form of construction of a nozzle arrangement in accordance with the invention.
[0026]In the preferred embodiment, ink is ejected out of a nozzle chamber via an ink ejection port using a series of radially positioned thermal actuator devices that are arranged about the ink ejection port and are activated to pressurize the ink within the nozzle chamber thereby causing the ejection of ink through the ejection port.
[0027]Turning now to FIGS. 1, 2 and 3, there is illustrated the basic operational principles of the preferred embodiment. FIG. 1 illustrates a single nozzle arrangement 1 in its quiescent state. The arrangement 1 includes a nozzle chamber 2 which is normally filled with ink so as to form a meniscus 3 in an ink ejection port 4. The nozzle chamber 2 is formed within a wafer 5. The nozzle chamber 2 is supplied with ink via an ink supply channel 6 which is etched through the wafer 5 with a highly isotropic plasma etching system. A suitable etcher can be the Advance Silicon Etch (ASE) system available from Surface Technology Systems of the United Kingdom.
[0028]A top of the nozzle arrangement 1 includes a series of radially positioned actuators 8, 9. These actuators comprise a polytetrafluoroethylene (PTFE) layer and an internal serpentine copper core 17. Upon heating of the copper core 17, the surrounding PTFE expands rapidly resulting in a generally downward movement of the actuators 8, 9. Hence, when it is desired to eject ink from the ink ejection port 4, a current is passed through the actuators 8, 9 which results in them bending generally downwards as illustrated in FIG. 2. The downward bending movement of the actuators 8, 9 results in a substantial increase in pressure within the nozzle chamber 2. The increase in pressure in the nozzle chamber 2 results in an expansion of the meniscus 3 as illustrated in FIG. 2.
[0029]The actuators 8, 9 are activated only briefly and subsequently deactivated. Consequently, the situation is as illustrated in FIG. 3 with the actuators 8, 9 returning to their original positions. This results in a general inflow of ink back into the nozzle chamber 2 and a necking and breaking of the meniscus 3 resulting in the ejection of a drop 12. The necking and breaking of the meniscus 3 is a consequence of the forward momentum of the ink associated with drop 12 and the backward pressure experienced as a result of the return of the actuators 8, 9 to their original positions. The return of the actuators 8, 9 also results in a general inflow of ink from the channel 6 as a result of surface tension effects and, eventually, the state returns to the quiescent position as illustrated in FIG. 1.
[0030]FIGS. 4(a) and 4(b) illustrate the principle of operation of the thermal actuator. The thermal actuator is preferably constructed from a material 14 having a high coefficient of thermal expansion. Embedded within the material 14 are a series of heater elements 15 which can be a series of conductive elements designed to carry a current. The conductive elements 15 are heated by passing a current through the elements 15 with the heating resulting in a general increase in temperature in the area around the heating elements 15. The position of the elements 15 is such that uneven heating of the material 14 occurs. The uneven increase in temperature causes a corresponding uneven expansion of the material 14. Hence, as illustrated in FIG. 4(b), the PTFE is bent generally in the direction shown.
[0031]In FIG. 5, there is illustrated a side perspective view of one embodiment of a nozzle arrangement constructed in accordance with the principles previously outlined. The nozzle chamber 2 is formed with an isotropic surface etch of the wafer 5. The wafer 5 can include a CMOS layer including all the required power and drive circuits. Further, the actuators 8, 9 each have a leaf or petal formation which extends towards a nozzle rim 28 defining the ejection port 4. The normally inner end of each leaf or petal formation is displaceable with respect to the nozzle rim 28. Each activator 8, 9 has an internal copper core 17 defining the element 15. The core 17 winds in a serpentine manner to provide for substantially unhindered expansion of the actuators 8, 9. The operation of the actuators 8, 9 is as illustrated in FIG. 4(a) and FIG. 4(b) such that, upon activation, the actuators 8 bend as previously described resulting in a displacement of each petal formation away from the nozzle rim 28 and into the nozzle chamber 2. The ink supply channel 6 can be created via a deep silicon back edge of the wafer 5 utilizing a plasma etcher or the like. The copper or aluminium core 17 can provide a complete circuit. A central arm 18 which can include both metal and PTFE portions provides the main structural support for the actuators 8, 9.
[0032]Turning now to FIG. 6 to FIG. 13, one form of manufacture of the nozzle arrangement 1 in accordance with the principles of the preferred embodiment is shown. The nozzle arrangement 1 is preferably manufactured using microelectromechanical (MEMS) techniques and can include the following construction techniques:
[0033]As shown initially in FIG. 6, the initial processing starting material is a standard semi-conductor wafer 20 having a complete CMOS level 21 to a first level of metal. The first level of metal includes portions 22 which are utilized for providing power to the thermal actuators 8, 9.
[0034]The first step, as illustrated in FIG. 7, is to etch a nozzle region down to the silicon wafer 20 utilizing an appropriate mask.
[0035]Next, as illustrated in FIG. 8, a 2 μm layer of polytetrafluoroethylene (PTFE) is deposited and etched so as to define vias 24 for interconnecting multiple levels.
[0036]Next, as illustrated in FIG. 9, the second level metal layer is deposited, masked and etched to define a heater structure 25. The heater structure 25 includes via 26 interconnected with a lower aluminium layer.
[0037]Next, as illustrated in FIG. 10, a further 2 μm layer of PTFE is deposited and etched to the depth of 1 μm utilizing a nozzle rim mask to define the nozzle rim 28 in addition to ink flow guide rails 29 which generally restrain any wicking along the surface of the PTFE layer. The guide rails 29 surround small thin slots and, as such, surface tension effects are a lot higher around these slots which in turn results in minimal outflow of ink during operation.
[0038]Next, as illustrated in FIG. 11, the PTFE is etched utilizing a nozzle and actuator mask to define a port portion 30 and slots 31 and 32.
[0039]Next, as illustrated in FIG. 12, the wafer is crystallographically etched on a <111> plane utilizing a standard crystallographic etchant such as KOH. The etching forms a chamber 33, directly below the port portion 30.
[0040]In FIG. 13, the ink supply channel 34 can be etched from the back of the wafer utilizing a highly anisotropic etcher such as the STS etcher from Silicon Technology Systems of United Kingdom. An array of ink jet nozzles can be formed simultaneously with a portion of an array 36 being illustrated in FIG. 14. A portion of the printhead is formed simultaneously and diced by the STS etching process. The array 36 shown provides for four column printing with each separate column attached to a different colour ink supply channel being supplied from the back of the wafer. Bond pads 37 provide for electrical control of the ejection mechanism.
[0041]In this manner, large pagewidth printheads can be fabricated so as to provide for a drop-on-demand ink ejection mechanism.
[0042]One form of detailed manufacturing process which can be used to fabricate monolithic ink jet printheads operating in accordance with the principles taught by the present embodiment can proceed utilizing the following steps:
[0043]1. Using a double-sided polished wafer 60, complete a 0.5 micron, one poly, 2 metal CMOS process 61. This step is shown in FIG. 16. For clarity, these diagrams may not be to scale, and may not represent a cross section though any single plane of the nozzle. FIG. 15 is a key to representations of various materials in these manufacturing diagrams, and those of other cross referenced ink jet configurations.
[0044]2. Etch the CMOS oxide layers down to silicon or second level metal using Mask 1. This mask defines the nozzle cavity and the edge of the chips. This step is shown in FIG. 16.
[0045]3. Deposit a thin layer (not shown) of a hydrophilic polymer, and treat the surface of this polymer for PTFE adherence.
[0046]4. Deposit 1.5 microns of polytetrafluoroethylene (PTFE) 62.
[0047]5. Etch the PTFE and CMOS oxide layers to second level metal using Mask 2. This mask defines the contact vias for the heater electrodes. This step is shown in FIG. 17.
[0048]6. Deposit and pattern 0.5 microns of gold 63 using a lift-off process using Mask 3. This mask defines the heater pattern. This step is shown in FIG. 18.
[0049]7. Deposit 1.5 microns of PTFE 64.
[0050]8. Etch 1 micron of PTFE using Mask 4. This mask defines the nozzle rim 65 and the rim at the edge 66 of the nozzle chamber. This step is shown in FIG. 19.
[0051]9. Etch both layers of PTFE and the thin hydrophilic layer down to silicon using Mask 5. This mask defines a gap 67 at inner edges of the actuators, and the edge of the chips. It also forms the mask for a subsequent crystallographic etch. This step is shown in FIG. 20.
[0052]10. Crystallographically etch the exposed silicon using KOH. This etch stops on <111> crystallographic planes 68, forming an inverted square pyramid with sidewall angles of 54.74 degrees. This step is shown in FIG. 21.
[0053]11. Back-etch through the silicon wafer (with, for example, an ASE Advanced Silicon Etcher from Surface Technology Systems) using Mask 6. This mask defines the ink inlets 69 which are etched through the wafer. The wafer is also diced by this etch. This step is shown in FIG. 22.
[0054]12. Mount the printheads in their packaging, which may be a molded plastic former incorporating ink channels which supply the appropriate color ink to the ink inlets 69 at the back of the wafer.
[0055]13. Connect the printheads 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.
[0056]14. Fill the completed print heads with ink 70 and test them. A filled nozzle is shown in FIG. 23.
[0057]The presently disclosed ink jet printing technology is potentially suited to a wide range of printing systems including: color 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 color and monochrome printers, color and monochrome copiers, color and monochrome facsimile machines, combined printer, facsimile and copying machines, label printers, large format plotters, photograph copiers, printers for digital photographic "minilabs", video printers, PHOTO CD (PHOTO CD is a registered trade mark of the Eastman Kodak Company) printers, portable printers for PDAs, wallpaper printers, indoor sign printers, billboard printers, fabric printers, camera printers and fault tolerant commercial printer arrays.
[0058]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.
[0059]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.
[0060]The most significant problem with thermal ink jet 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 ink jet applications. This leads to an efficiency of around 0.02%, from electricity input to drop momentum (and increased surface area) out.
[0061]The most significant problem with piezoelectric ink jet 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 printhead, but is a major impediment to the fabrication of pagewidth printheads with 19,200 nozzles.
[0062]Ideally, the ink jet 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 ink jet technologies have been created. The target features include:
[0063]low power (less than 10 Watts)
[0064]high resolution capability (1,600 dpi or more)
[0065]photographic quality output
[0066]low manufacturing cost
[0067]small size (pagewidth times minimum cross section)
[0068]high speed (<2 seconds per page).
[0069]All of these features can be met or exceeded by the ink jet systems described below with differing levels of difficulty. Forty-five different ink jet 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 under the heading
[0070]The ink jet 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.
[0071]For ease of manufacture using standard process equipment, the printhead is designed to be a monolithic 0.5 micron CMOS chip with MEMS post processing. For color photographic applications, the printhead is 100 mm long, with a width which depends upon the inkjet type. The smallest printhead designed is IJ38, which is 0.35 mm wide, giving a chip area of 35 square mm. The printheads each contain 19,200 nozzles plus data and control circuitry.
[0072]Ink is supplied to the back of the printhead 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 printhead is connected to the camera circuitry by tape automated bonding.
[0073]Eleven important characteristics of the fundamental operation of individual ink jet 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.
[0074]The following tables form the axes of an eleven dimensional table of ink jet types.
[0075]Actuator mechanism (18 types)
[0076]Basic operation mode (7 types)
[0077]Auxiliary mechanism (8 types)
[0078]Actuator amplification or modification method (17 types)
[0079]Actuator motion (19 types)
[0080]Nozzle refill method (4 types)
[0081]Method of restricting back-flow through inlet (10 types)
[0082]Nozzle clearing method (9 types)
[0083]Nozzle plate construction (9 types)
[0084]Drop ejection direction (5 types)
[0085]Ink type (7 types)
[0086]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 ink jet technology, many million configurations are viable. It is clearly impractical to elucidate all of the possible configurations. Instead, certain ink jet types have been investigated in detail. These are designated IJ01 to IJ45 above which matches the docket numbers in the table under the heading
[0087]Other inkjet configurations can readily be derived from these forty-five examples by substituting alternative configurations along one or more of the 11 axes. Most of the IJ01 to IJ45 examples can be made into ink jet printheads with characteristics superior to any currently available ink jet technology.
[0088]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, print technology may be listed more than once in a table, where it shares characteristics with more than one entry.
[0089]Suitable applications for the ink jet technologies 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.
[0090]The information associated with the aforementioned 11 dimensional matrix are set out in the following tables.
TABLE-US-00009 NOZZLE CLEARING METHOD Description Advantages Disadvantages Examples Normal All of the nozzles No added May not be Most ink jet nozzle are fired complexity on sufficient to systems firing periodically, the print head displace dried IJ01, IJ02, before the ink has ink IJ03, IJ04, IJ05, a chance to dry. IJ06, IJ07, IJ09, When not in use IJ10, IJ11, IJ12, the nozzles are IJ14, IJ16, IJ20, sealed (capped) IJ22, IJ23, IJ24, against air. IJ25, IJ26, IJ27, The nozzle firing IJ28, IJ29, IJ30, is usually IJ31, IJ32, IJ33, performed during a IJ34, IJ36, IJ37, special clearing IJ38, IJ39, IJ40,, cycle, after first IJ41, IJ42, IJ43, moving the print IJ44,, IJ45 head to a cleaning station. Extra In systems which Can be highly Requires Silverbrook, power to heat the ink, but do effective if the higher drive EP 0771 658 A2 ink heater not boil it under heater is voltage for and related normal situations, adjacent to the clearing patent nozzle clearing can nozzle May require applications be achieved by larger drive over-powering the transistors heater and boiling ink at the nozzle. Rapid The actuator is Does not Effectiveness May be used succession fired in rapid require extra depends with: IJ01, IJ02, of succession. In drive circuits on substantially IJ03, IJ04, IJ05, actuator some the print head upon the IJ06, IJ07, IJ09, pulses configurations, this Can be readily configuration of IJ10, IJ11, IJ14, may cause heat controlled and the ink jet nozzle IJ16, IJ20, IJ22, build-up at the initiated by IJ23, IJ24, IJ25, nozzle which boils digital logic IJ27, IJ28, IJ29, the ink, clearing IJ30, IJ31, IJ32, the nozzle. In other IJ33, IJ34, IJ36, situations, it may IJ37, IJ38, IJ39, cause sufficient IJ40, IJ41, IJ42, vibrations to IJ43, IJ44, IJ45 dislodge clogged nozzles. Extra Where an actuator A simple Not suitable May be used power to is not normally solution where where there is a with: IJ03, IJ09, ink driven to the limit applicable hard limit to IJ16, IJ20, IJ23, pushing of its motion, actuator IJ24, IJ25, IJ27, actuator nozzle clearing movement IJ29, IJ30, IJ31, may be assisted by IJ32, IJ39, IJ40, providing an IJ41, IJ42, IJ43, enhanced drive IJ44, IJ45 signal to the actuator. Acoustic An ultrasonic A high nozzle High IJ08, IJ13, resonance wave is applied to clearing implementation IJ15, IJ17, IJ18, the ink chamber. capability can be cost if system IJ19, IJ21 This wave is of an achieved does not already appropriate May be include an amplitude and implemented at acoustic actuator frequency to cause very low cost in sufficient force at systems which the nozzle to clear already include blockages. This is acoustic easiest to achieve actuators if the ultrasonic wave is at a resonant frequency of the ink cavity. Nozzle A microfabricated Can clear Accurate Silverbrook, clearing plate is pushed severely clogged mechanical EP 0771 658 A2 plate against the nozzles alignment is and related nozzles. The plate required patent has a post for Moving parts applications every nozzle. A are required post moves There is risk through each of damage to the nozzle, displacing nozzles dried ink. Accurate fabrication is required Ink The pressure of the May be Requires May be used pressure ink is temporarily effective where pressure pump with all IJ series pulse increased so that other methods or other pressure ink jets ink streams from cannot be used actuator all of the nozzles. Expensive This may be used Wasteful of in conjunction ink with actuator energizing. Print A flexible `blade` Effective for Difficult to Many ink jet head is wiped across the planar print head use if print head systems wiper print head surface. surfaces surface is non- The blade is Low cost planar or very usually fabricated fragile from a flexible Requires polymer, e.g. mechanical parts rubber or synthetic Blade can elastomer. wear out in high volume print systems Separate A separate heater Can be Fabrication Can be used ink is provided at the effective where complexity with many IJ boiling nozzle although other nozzle series ink jets heater the normal drop e- clearing methods ection mechanism cannot be used does not require it. Can be The heaters do not implemented at require individual no additional drive circuits, as cost in some ink many nozzles can jet be cleared configurations simultaneously, and no imaging is required.
TABLE-US-00010 NOZZLE PLATE CONSTRUCTION Description Advantages Disadvantages Examples Electro- A nozzle plate is Fabrication High Hewlett formed separately simplicity temperatures and Packard Thermal nickel fabricated from pressures are Ink jet electroformed required to bond nickel, and bonded nozzle plate to the print head Minimum chip. thickness constraints Differential thermal expansion Laser Individual nozzle No masks Each hole Canon ablated or holes are ablated required must be Bubblejet drilled by an intense UV Can be quite individually 1988 Sercel et polymer laser in a nozzle fast formed al., SPIE, Vol. plate, which is Some control Special 998 Excimer typically a over nozzle equipment Beam polymer such as profile is required Applications, pp. polyimide or possible Slow where 76-83 polysulphone Equipment there are many 1993 required is thousands of Watanabe et al., relatively low nozzles per print U.S. Pat. No. 5,208,604 cost head May produce thin burrs at exit holes Silicon A separate nozzle High accuracy Two part K. Bean, micro- plate is is attainable construction IEEE machined micromachined High cost Transactions on from single crystal Requires Electron silicon, and precision Devices, Vol. bonded to the print alignment ED-25, No. 10, head wafer. Nozzles may 1978, pp 1185-1195 be clogged by Xerox 1990 adhesive Hawkins et al., U.S. Pat. No. 4,899,181 Glass Fine glass No expensive Very small 1970 Zoltan capillaries capillaries are equipment nozzle sizes are U.S. Pat. No. 3,683,212 drawn from glass required difficult to form tubing. This Simple to Not suited for method has been make single mass production used for making nozzles individual nozzles, but is difficult to use for bulk manufacturing of print heads with thousands of nozzles. Monolithic, The nozzle plate is High accuracy Requires Silverbrook, surface deposited as a (<1 μm) sacrificial layer EP 0771 658 A2 micro- layer using Monolithic under the nozzle and related machined standard VLSI Low cost plate to form the patent using deposition Existing nozzle chamber applications VLSI techniques. processes can be Surface may IJ01, IJ02, litho- Nozzles are etched used be fragile to the IJ04, IJ11, IJ12, graphic in the nozzle plate touch IJ17, IJ18, IJ20, processes using VLSI IJ22, IJ24, IJ27, lithography and IJ28, IJ29, IJ30, etching. IJ31, IJ32, IJ33, IJ34, IJ36, IJ37, IJ38, IJ39, IJ40, IJ41, IJ42, IJ43, IJ44 Monolithic, The nozzle plate is High accuracy Requires long IJ03, IJ05, etched a buried etch stop (<1 μm) etch times IJ06, IJ07, IJ08, through in the wafer. Monolithic Requires a IJ09, IJ10, IJ13, substrate Nozzle chambers Low cost support wafer IJ14, IJ15, IJ16, are etched in the No differential IJ19, IJ21, IJ23, front of the wafer, expansion IJ25, IJ26 and the wafer is thinned from the back side. Nozzles are then etched in the etch stop layer. No nozzle Various methods No nozzles to Difficult to Ricoh 1995 plate have been tried to become clogged control drop Sekiya et al U.S. Pat. No. eliminate the position 5,412,413 nozzles entirely, to accurately 1993 prevent nozzle Crosstalk Hadimioglu et al clogging. These problems EUP 550,192 include thermal 1993 Elrod et bubble al EUP 572,220 mechanisms and acoustic lens mechanisms Trough Each drop ejector Reduced Drop firing IJ35 has a trough manufacturing direction is through which a complexity sensitive to paddle moves. Monolithic wicking. There is no nozzle plate. Nozzle slit The elimination of No nozzles to Difficult to 1989 Saito et instead of nozzle holes and become clogged control drop al U.S. Pat. No. individual replacement by a position 4,799,068 nozzles slit encompassing accurately many actuator Crosstalk positions reduces problems nozzle clogging, but increases crosstalk due to ink surface waves
TABLE-US-00011 DROP EJECTION DIRECTION Description Advantages Disadvantages Examples Edge Ink flow is along Simple Nozzles Canon (`edge the surface of the construction limited to edge Bubblejet 1979 shooter`) chip, and ink drops No silicon High Endo et al GB are ejected from etching required resolution is patent 2,007,162 the chip edge. Good heat difficult Xerox heater- sinking via Fast color in-pit 1990 substrate printing requires Hawkins et al Mechanically one print head U.S. Pat. No. 4,899,181 strong per color Tone-jet Ease of chip handing Surface Ink flow is along No bulk Maximum ink Hewlett- (`roof the surface of the silicon etching flow is severely Packard TIJ shooter`) chip, and ink drops required restricted 1982 Vaught et are ejected from Silicon can al U.S. Pat. No. the chip surface, make an 4,490,728 normal to the effective heat IJ02, IJ11, plane of the chip. sink IJ12, IJ20, IJ22 Mechanical strength Through Ink flow is through High ink flow Requires bulk Silverbrook, chip, the chip, and ink Suitable for silicon etching EP 0771 658 A2 forward drops are ejected pagewidth print and related (`up from the front heads patent shooter`) surface of the chip. High nozzle applications packing density IJ04, IJ17, therefore low IJ18, IJ24, IJ27-IJ45 manufacturing cost Through Ink flow is through High ink flow Requires IJ01, IJ03, chip, the chip, and ink Suitable for wafer thinning IJ05, IJ06, IJ07, reverse drops are ejected pagewidth print Requires IJ08, IJ09, IJ10, (`down from the rear heads special handling IJ13, IJ14, IJ15, shooter`) surface of the chip. High nozzle during IJ16, IJ19, IJ21, packing density manufacture IJ23, IJ25, IJ26 therefore low manufacturing cost Through Ink flow is through Suitable for Pagewidth Epson Stylus actuator the actuator, which piezoelectric print heads Tektronix hot is not fabricated as print heads require several melt part of the same thousand piezoelectric ink substrate as the connections to jets drive transistors. drive circuits Cannot be manufactured in standard CMOS fabs Complex assembly required
TABLE-US-00012 INK TYPE Description Advantages Disadvantages Examples Aqueous, Water based ink Environmentally Slow drying Most existing dye which typically friendly Corrosive ink jets contains: water, No odor Bleeds on All IJ series dye, surfactant, paper ink jets humectant, and May Silverbrook, biocide. strikethrough EP 0771 658 A2 Modern ink dyes Cockles paper and related have high water- patent fastness, light applications fastness Aqueous, Water based ink Environmentally Slow drying IJ02, IJ04, pigment which typically friendly Corrosive IJ21, IJ26, IJ27, contains: water, No odor Pigment may IJ30 pigment, Reduced bleed clog nozzles Silverbrook, surfactant, Reduced Pigment may EP 0771 658 A2 humectant, and wicking clog actuator and related biocide. Reduced mechanisms patent Pigments have an strikethrough Cockles paper applications advantage in Piezoelectric reduced bleed, ink-jets wicking and Thermal ink strikethrough. jets (with significant restrictions) Methyl MEK is a highly Very fast Odorous All IJ series Ethyl volatile solvent drying Flammable ink jets Ketone used for industrial Prints on (MEK) printing on various difficult surfaces substrates such such as aluminum as metals and cans. plastics Alcohol Alcohol based inks Fast drying Slight odor All IJ series (ethanol, can be used where Operates at Flammable ink jets 2-butanol, the printer must sub-freezing and operate at temperatures others) temperatures Reduced below the freezing paper cockle point of water. An Low cost example of this is in-camera consumer photographic printing. Phase The ink is solid at No drying High viscosity Tektronix hot change room temperature, time-ink Printed ink melt (hot melt) and is melted in instantly freezes typically has a piezoelectric ink the print head on the print `waxy` feel jets before jetting. Hot medium Printed pages 1989 Nowak melt inks are Almost any may `block` U.S. Pat. No. 4,820,346 usually wax based, print medium Ink All IJ series with a melting can be used temperature may ink jets point around 80° C.. No paper be above the After jetting cockle occurs curie point of the ink freezes No wicking permanent almost instantly occurs magnets upon contacting No bleed Ink heaters the print medium occurs consume power or a transfer roller. No Long warm- strikethrough up time occurs Oil Oil based inks are High High All IJ series extensively used in solubility viscosity: this is ink jets offset printing. medium for a significant They have some dyes limitation for use advantages in Does not in ink jets, which improved cockle paper usually require a characteristics on Does not wick low viscosity. paper (especially through paper Some short no wicking or chain and multi- cockle). Oil branched oils soluble dies and have a pigments are sufficiently low required. viscosity. Slow drying Microemulsion A microemulsion Stops ink Viscosity All IJ series is a stable, self bleed higher than ink jets forming emulsion High dye water of oil, water, and solubility Cost is surfactant. The Water, oil, slightly higher characteristic drop and amphiphilic than water based size is less than soluble dies can ink 100 nm, and is be used High determined by the Can stabilize surfactant preferred curvature pigment concentration of the surfactant. suspensions required (around 5%)
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2009-10-01 Nozzle arrangement having annulus shaped heater elements
2012-12-27 Light beam emission apparatus, optical scanning apparatus including the light beam emission apparatus, and image forming apparatus including the optical scanning apparatus
2009-03-12 Printhead with increasing drive pulse to counter heater oxide growth