Patent Publication Number: US-6213588-B1

Title: Electrostatic ink jet printing mechanism

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     The following Australian provisional patent applications are hereby incorporated by cross-reference. For the purposes of location and identification, US patent applications identified by their US patent application serial numbers (USSN) are listed alongside the Australian applications from which the US patent applications claim the right of priority. 
     
       
         
           
               
               
               
             
               
                   
               
               
                 CROSS-REFERENCED 
                 U.S. patent application 
                   
               
               
                 AUSTRALIAN 
                 (CLAIMING RIGHT OF PRIORITY 
               
               
                 PROVISIONAL 
                 FROM AUSTRALIAN 
                 DOCKET 
               
               
                 PATENT NO. 
                 PROVISIONAL APPLICATION) 
                 NO. 
               
               
                   
               
             
            
               
                 PO7991 
                 09/113,060 
                 ART01 
               
               
                 PO8505 
                 09/113,070 
                 ART02 
               
               
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                 ART03 
               
               
                 PO9395 
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                 ART04 
               
               
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                 ART06 
               
               
                 PO8014 
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                 ART07 
               
               
                 PO8025 
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                 ART08 
               
               
                 PO8032 
                 09/112,746 
                 ART09 
               
               
                 PO7999 
                 09/112,743 
                 ART10 
               
               
                 PO7998 
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                 ART11 
               
               
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                 ART12 
               
               
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                 ART13 
               
               
                 PO7997 
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                 ART15 
               
               
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                 09/113,053 
                 ART16 
               
               
                 PO8015 
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                 ART17 
               
               
                 PO7978 
                 09/113,067 
                 ART18 
               
               
                 PO7982 
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                 ART19 
               
               
                 PO7989 
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                 ART20 
               
               
                 PO8019 
                 09/112,744 
                 ART21 
               
               
                 PO7980 
                 09/113,058 
                 ART22 
               
               
                 PO8018 
                 09/112,777 
                 ART24 
               
               
                 PO7938 
                 09/113,224 
                 ART25 
               
               
                 PO8016 
                 09/112,804 
                 ART26 
               
               
                 PO8024 
                 09/112,805 
                 ART27 
               
               
                 PO7940 
                 09/113,072 
                 ART28 
               
               
                 PO7939 
                 09/112,785 
                 ART29 
               
               
                 PO8501 
                 09/112,797 
                 ART30 
               
               
                 PO8500 
                 09/112,796 
                 ART31 
               
               
                 PO7940 
                 09/113,072 
                 ART28 
               
               
                 PO7939 
                 09/112,785 
                 ART29 
               
               
                 PO8501 
                 09/112,797 
                 ART30 
               
               
                 PO8500 
                 09/112,796 
                 ART31 
               
               
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                 ART32 
               
               
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                 ART33 
               
               
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                 ART34 
               
               
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                 ART38 
               
               
                 PO8023 
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                 ART39 
               
               
                 PO8504 
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                 ART42 
               
               
                 PO8000 
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                 ART43 
               
               
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                 ART44 
               
               
                 PO7934 
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                 ART45 
               
               
                 PO7990 
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                 ART46 
               
               
                 PO8499 
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                 ART47 
               
               
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                 ART48 
               
               
                 PO7981 
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                 ART50 
               
               
                 PO7986 
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                 ART51 
               
               
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                 ART52 
               
               
                 PO8026 
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                 ART53 
               
               
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                 ART54 
               
               
                 PO8028 
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                 ART56 
               
               
                 PO9394 
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                 ART57 
               
               
                 PO9396 
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                 ART58 
               
               
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                 ART59 
               
               
                 PO9398 
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                 ART60 
               
               
                 PO9399 
                 09/112,791 
                 ART61 
               
               
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                 ART62 
               
               
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                 ART63 
               
               
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                 09/112,788 
                 ART64 
               
               
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                 09/112,795 
                 ART65 
               
               
                 PO9405 
                 09/112,749 
                 ART66 
               
               
                 PPO959 
                 09/112,784 
                 ART68 
               
               
                 PP1397 
                 09/112,783 
                 ART69 
               
               
                 PP2370 
                 09/112,781 
                 DOT01 
               
               
                 PP2371 
                 09/113,052 
                 DOT02 
               
               
                 PO8003 
                 09/112,834 
                 Fluid01 
               
               
                 PO8005 
                 09/113,103 
                 Fluid02 
               
               
                 PO9404 
                 09/113,101 
                 Fluid03 
               
               
                 PO8066 
                 09/112,751 
                 IJ01 
               
               
                 PO8072 
                 09/112,787 
                 IJ02 
               
               
                 PO8040 
                 09/112,802 
                 IJ03 
               
               
                 PO8071 
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                 IJ04 
               
               
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                 IJ05 
               
               
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                 IJ06 
               
               
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                 IJ07 
               
               
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                 IJ08 
               
               
                 PO8057 
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                 IJ09 
               
               
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                 IJ10 
               
               
                 PO8069 
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                 IJ11 
               
               
                 PO8049 
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                 1J12 
               
               
                 PO8036 
                 09/112,818 
                 1J13 
               
               
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                 1J14 
               
               
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                 IJ15 
               
               
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                 IJ16 
               
               
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                 IJ17 
               
               
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                 IJ18 
               
               
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                 IJ19 
               
               
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                 IJ20 
               
               
                 PO8068 
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                 IJ21 
               
               
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                 IJ22 
               
               
                 PO8034 
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                 IJ23 
               
               
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                 IJ24 
               
               
                 PO8041 
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                 IJ25 
               
               
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                 IJ26 
               
               
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                 IJ27 
               
               
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                 IJ28 
               
               
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                 IJ29 
               
               
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                 IJ30 
               
               
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                 IJ31 
               
               
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                 IJ32 
               
               
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                 IJ33 
               
               
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                 IJ34 
               
               
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                 IJ35 
               
               
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                 IJ36 
               
               
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                 IJ37 
               
               
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                 IJ38 
               
               
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                 IJ39 
               
               
                 PP2592 
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                 IJ40 
               
               
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                 IJ41 
               
               
                 PP3991 
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                 IJ42 
               
               
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                 IJ43 
               
               
                 PP3985 
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                 IJ44 
               
               
                 PP3983 
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                 IJ45 
               
               
                 PO7935 
                 09/112,822 
                 IJM01 
               
               
                 PO7936 
                 09/112,825 
                 IJM02 
               
               
                 PO7937 
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                 IJM03 
               
               
                 PO8061 
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                 IJM04 
               
               
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                 IJM05 
               
               
                 PO8065 
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                 IJM06 
               
               
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                 IJM07 
               
               
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                 IJM08 
               
               
                 PO8078 
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                 IJM09 
               
               
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                 IJM10 
               
               
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                 IJM11 
               
               
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                 IJM12 
               
               
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                 IJM45 
               
               
                 PP0895 
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                 IR01 
               
               
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                 IR02 
               
               
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                 IR04 
               
               
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                 IR20 
               
               
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                 IR21 
               
               
                 PO8006 
                 09/113,100 
                 MEMS02 
               
               
                 PO8007 
                 09/113,093 
                 MEMS03 
               
               
                 PO8008 
                 09/113,062 
                 MEMS04 
               
               
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                 09/113,064 
                 MEMS05 
               
               
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                 09/113,082 
                 MEMS06 
               
               
                 PO7947 
                 09/113,081 
                 MEMS07 
               
               
                 PO7944 
                 09/113,080 
                 MEMS09 
               
               
                 PO7946 
                 09/113,079 
                 MEMS10 
               
               
                 PO9393 
                 09/113,065 
                 MEMS11 
               
               
                 PP0875 
                 09/113,078 
                 MEMS12 
               
               
                 PP0894 
                 09/113,075 
                 MEMS13 
               
               
                   
               
            
           
         
       
     
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     FIELD OF THE INVENTION 
     The present invention relates to ink jet printing and in particular discloses an Electrostatic Ink Jet Printer. 
     The present invention further relates to the field of drop on demand ink jet printing. 
     BACKGROUND OF THE INVENTION 
     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. 
     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. 
     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). 
     Ink Jet printers themselves come in many different types. The utilisation 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 electro-static ink jet printing. 
     U.S. Pat. No. 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) 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 utilises 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 piezoelectric 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 Piezoelectric 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 piezoelectric transducer element. 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 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 utilising the electro-thermal actuator are manufactured by manufacturers such as Canon and Hewlett Packard. 
     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. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a new form of ink jet printing wherein the ink is ejected from a nozzle chamber by means of the utilization of the electrostatic attraction between two parallel plates. 
     In accordance with the first aspect of the present invention there is provided an ink jet nozzle comprising a nozzle chamber having an ink ejection port in one wall of the chamber, an ink supply source interconnected to the nozzle chamber, an electrostatic actuator comprising a first planar electrode formed within a bottom substrate of the nozzle chamber and a moveable second planar electrode arranged above the first planar electrode, wherein the second planar electrode is moveable to a pre-firing position adjacent to said first planar electrode, upon forming a potential difference across the electrodes, thereby causing a corrugated border portion of the second electrode to concertina, such that, upon reduction of the potential difference, the corrugated border returns to its quiescent position and thereby causes the ejection of ink from the nozzle chamber. 
     In accordance with the second aspect of the present invention there is provided an ink jet nozzle comprising a nozzle chamber having an ink ejection port in one wall of the chamber, an ink supply source interconnected to the nozzle chamber, an electrostatic actuator to eject ink from the nozzle chamber via the ink ejection port, wherein the electrostatic actuator comprises a first planar electrode formed within a bottom substrate of the nozzle chamber and a moveable second planar electrode arranged above the first planar electrode, and the ink jet nozzle arrangement is being formed from the depositing and etching of material on a single monolithic wafer. Further, there is an air gap between the first and second planar electrode which is interconnected to an external atmosphere at a side of the nozzle chamber such that air flows into and out of the gap upon movement of the actuator. Preferably the surface of the electrodes facing and opposing electrode are coated with a material having a low coefficient of friction so as to reduce the possibilities of stiction. Advantageously this material comprised of substantially polytetrafluoroethylene. The second planar electrode includes preferable a layer of stiffening materials for maintaining the stiffness of the second planar electrode which is substantially comprised of nitride. The air gap between a first and a second planar electrode structure is formed by utilization of a sacrificial material layer which is etched away to release the second planar electrode structure. 
     Further an outer surface of the ink chamber includes a plurality of etchant holes provided so as to allow a more rapid etching of sacrificial layers during construction. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     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, which: 
     FIG. 1 is a perspective cross-sectional view of a single ink jet nozzle constructed in accordance with the preferred embodiment; 
     FIG. 2 is a close-up perspective cross-sectional view (portion A of FIG.  1 ), of a single ink jet nozzle constructed in accordance with the preferred embodiment; 
     FIG. 3 is an exploded perspective view illustrating the construction of a single ink jet nozzle in accordance with the preferred embodiment; 
     FIG. 4 provides a legend of the materials indicated in FIGS. 5 to  15 ; and 
     FIG. 5 to FIG. 15 illustrate sectional views of the manufacturing steps in one form of construction of an ink jet printhead nozzle. 
    
    
     DESCRIPTION OF PREFERRED AND OTHER EMBODIMENTS 
     In the preferred embodiment, an ink jet print head is made up of a plurality of nozzle chambers each having an ink ejection port. Ink is ejected from the ink ejection port through the utilization of attraction between two parallel plates. 
     Turning initially to FIG. 1, there is illustrated a cross-sectional view of a single nozzle arrangement  10  as constructed in accordance with the preferred embodiment. The nozzle arrangement  10  includes a nozzle chamber  11  in which is stored ink to be ejected out of an ink ejection port  12 . The nozzle arrangement  10  can be constructed on the top of a silicon wafer utilizing micro electro-mechanical systems construction techniques as will become more apparent hereinafter. The top of the nozzle plate also includes a series of regular spaced etchant holes, e.g.  13  which are provided for efficient sacrificial etching of lower layers of the nozzle arrangement  10  during construction. The size of the etchant holes  13  is small enough that surface tension characteristics inhibit ejection from the holes  13  during operation. 
     Ink is supplied to the nozzle chamber  11  via an ink supply channel, e.g.  15 . 
     Turning now to FIG. 2, there is illustrated a cross-sectional view of one side of the nozzle arrangement  10 . A nozzle arrangement  10  is constructed on a silicon wafer base  17  on top of which is first constructed a standard CMOS two level metal layer  18  which includes the required drive and control circuitry for each nozzle arrangement. The layer  18 , which includes two levels of aluminum, includes one level of aluminum  19  being utilized as a bottom electrode plate. Other portions  20  of this layer can comprise nitride passivation. On top of the layer  19  there is provided a thin polytetrafluoroethylene (PTFE) layer  21 . 
     Next, an air gap  27  is provided between the top and bottom layers. This is followed by a further PTFE layer  28  which forms part of the top plate  22 . The two PTFE layers  21 ,  28  are provided so as to reduce possible stiction effects between the upper and lower plates. Next, a top aluminum electrode layer  30  is provided followed by a nitride layer (not shown) which provides structural integrity to the top electro plate. The layers  28 - 30  are fabricated so as to include a corrugated portion  23  which concertinas upon movement of the top plate  22 . 
     By placing a potential difference across the two aluminum layers  19  and  30 , the top plate  22  is attracted to bottom aluminum layer  19  thereby resulting in a movement of the top plate  22  towards the bottom plate  19 . This results in energy being stored in the concertinaed spring arrangement  23  in addition to air passing out of the side air holes, e.g.  33  and the ink being sucked into the nozzle chamber as a result of the distortion of the meniscus over the ink ejection port  12  (FIG.  1 ). Subsequently, the potential across the plates is eliminated thereby causing the concertinaed spring portion  23  to rapidly return the plate  22  to its rest position. The rapid movement of the plate  22  causes the consequential ejection of ink from the nozzle chamber via the ink ejection port  12  (FIG.  1 ). Additionally, air flows in via air gap  33  underneath the plate  22 . 
     The ink jet nozzles of the preferred embodiment can be formed from utilization of semiconductor fabrication and MEMS techniques. Turning to FIG. 3, there is illustrated an exploded perspective view of the various layers in the final construction of a nozzle arrangement  10 . At the lowest layer is the silicon wafer  17  upon which all other processing steps take place. On top of the silicon layer  17  is the CMOS circuitry layer  18  which primarily comprises glass. On top of this layer is a nitride passivation layer  20  which is primarily utilized to passivate and protect the lower glass layer from any sacrificial process that may be utilized in the building up of subsequent layers. 
     Next there is provided the aluminum layer  19  which, in the alternative, can form part of the lower CMOS glass layer  18 . This layer  19  forms the bottom plate. Next, two PTFE layers  26 ,  28  are provided between which is laid down a sacrificial layer, such as glass, which is subsequently etched away so as to release the plate  22  (FIG.  2 ). On top of the PTFE layer  28  is laid down the aluminum layer  30  and a subsequent thicker nitride layer (not shown) which provides structural support to the top electrode stopping it from sagging or deforming. After this comes the top nitride nozzle chamber layer  35  which forms the rest of the nozzle chamber and ink supply channel. The layer  35  can be formed from the depositing and etching of a sacrificial layer and then depositing the nitride layer, etching the nozzle and etchant holes utilizing an appropriate mask before etching away the sacrificial material. 
     Obviously, print heads can be formed from large arrays of nozzle arrangements  10  on a single wafer which is subsequently diced into separate print heads. Ink supply can be either from the side of the wafer or through the wafer utilizing deep anisotropic etching systems such as high density low pressure plasma etching systems available from surface technology systems. Further, the corrugated portion  23  can be formed through the utilisation of a half tone mask process. 
     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: 
     1. Using a double sided polished wafer  40 , complete a 0.5 micron, one poly, 2 metal CMOS process  42 . This step is shown in FIG.  5 . For clarity, these diagrams may not be to scale, and may not represent a cross section though any single plane of the nozzle. FIG. 4 is a key to representations of various materials in these manufacturing diagrams, and those of other cross referenced ink jet configurations. FIG. 4 is a key to representations of various materials in these manufacturing diagrams, and those of other cross referenced ink jet configurations. 
     2. Etch the passivation layers  46  to expose the bottom electrode  44 , formed of second level metal. This etch is performed using Mask  1 . This step is shown in FIG.  6 . 
     3. Deposit 50 nm of PTFE or other highly hydrophobic material. 
     4. Deposit 0.5 microns of sacrificial material, e.g. polyimide  48 . 
     5. Deposit 0.5 microns of (sacrificial) photosensitive polyimide. 
     6. Expose and develop the photosensitive polyimide using Mask  2 . This mask is a gray-scale mask which defines the concertina edge  50  of the upper electrode. The result of the etch is a series of triangular ridges at the circumference of the electrode. This concertina edge is used to convert tensile stress into bend strain, and thereby allow the upper electrode to move when a voltage is applied across the electrodes. This step is shown in FIG.  7 . 
     7. Etch the polyimide and passivation layers using Mask  3 , which exposes the contacts for the upper electrode which are formed in second level metal. 
     8. Deposit 0.1 microns of tantalum  52 , forming the upper electrode. 
     9. Deposit 0.5 microns of silicon nitride (Si3N4), which forms the movable membrane of the upper electrode. 
     10. Etch the nitride and tantalum using Mask  4 . This mask defines the upper electrode, as well as the contacts to the upper electrode. This step is shown in FIG.  8 . 
     11. Deposit 12 microns of (sacrificial) photosensitive polyimide  54 . 
     12. Expose and develop the photosensitive polyimide using Mask  5 . A proximity aligner can be used to obtain a large depth of focus, as the line-width for this step is greater than 2 microns, and can be 5 microns or more. This mask defines the nozzle chamber walls. This step is shown in FIG.  9 . 
     13. Deposit 3 microns of PECVD glass  56 . This step is shown in FIG.  10 . 
     14. Etch to a depth of 1 micron using Mask  6 . This mask defines the nozzle rim  58 . This step is shown in FIG.  11 . 
     15. Etch down to the sacrificial layer  54  using Mask  7 . This mask defines the roof of the nozzle chamber, and the nozzle  60  itself. This step is shown in FIG.  12 . 
     16. Back-etch completely through the silicon wafer  46  (with, for example, an ASE Advanced Silicon Etcher from Surface Technology Systems) using Mask  8 . This mask defines the ink inlets  62  which are etched through the wafer  40 . The wafer  40  is also diced by this etch. 
     17. Back-etch through the CMOS oxide layer through the holes in the wafer  40 . This step is shown in FIG.  13 . 
     18. Etch the sacrificial polyimide  54 . The nozzle chambers  64  are cleared, a gap is formed between the electrodes and the chips are separated by this etch. To avoid stiction, a final rinse using supercooled carbon dioxide can be used. This step is shown in FIG.  14 . 
     19. 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. 
     20. 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. 
     21. Hydrophobize the front surface of the print heads. 
     22. Fill the completed print heads with ink  66  and test them. A filled nozzle is shown in FIG.  15 . 
     The aforementioned half-tone mask process follows fabrication steps as discussed in Australian Provisional Patent entitled Image Creation Method and Apparatus United Sates Patent (IJ16) lodged by the present applicant simultaneously herewith, the contents of which are hereby incorporated by cross-reference. 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 preferred embodiment without departing from the spirit or scope of the invention as broadly described. The preferred embodiment is, therefore, to be considered in all respects to be illustrative and not restrictive. 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 in-built 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. 
     Ink Jet Technologies 
     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. 
     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. 
     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. 
     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: 
     low power (less than 10 Watts) 
     high resolution capability (1,600 dpi or more) 
     photographic quality output 
     low manufacturing cost 
     small size (pagewidth times minimum cross section) 
     high speed (&lt;2 seconds per page). 
     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 under the heading Cross References to Related Applications. 
     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. 
     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 ink jet 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. 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 print head printhead is connected to the camera circuitry by tape automated bonding. 
     Tables of Drop-on-Demand Ink Jets 
     The present invention is useful in the field of digital printing, in particular, ink jet printing. 
     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. 
     The following tables form the axes of an eleven dimensional table of ink jet types. 
     Actuator mechanism (18 types) 
     Basic operation mode (7 types) 
     Auxiliary mechanism (8 types) 
     Actuator amplification or modification method (17 types) 
     Actuator motion (19 types) 
     Nozzle refill method (4 types) 
     Method of restricting back-flow through inlet (10 types) 
     Nozzle clearing method (9 types) 
     Nozzle plate construction (9 types) 
     Drop ejection direction (5 types) 
     Ink type (7 types) 
     The complete eleven dimensional table represented by these axes contains 36.9 billion possible configurations of ink jet 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 which matches the docket numbers in the table under the heading Cross References to Related Applications. 
     Other ink jet 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. 
     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 print technology may be listed more than once in a table, where it shares characteristics with more than one entry. 
     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. 
     The information associated with the aforementioned 11 dimensional matrix are set out in the following tables. 
     
       
         
           
               
               
               
               
               
             
               
                   
                   
               
               
                   
                 Description 
                 Advantages 
                 Disadvantages 
                 Examples 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
            
               
                 Actuator mechanism (applied only to selected ink drops) 
               
            
           
           
               
               
               
               
               
            
               
                 Thermal 
                 An electrothermal 
                 Large force 
                 High power 
                 Canon Bubblejet 1979 
               
               
                 bubble 
                 heater heats the ink 
                 generated 
                 Ink carrier limited 
                 Endo et al GB patent 
               
               
                   
                 to above boiling 
                 Simple 
                 to water 
                 2,007,162 
               
               
                   
                 point, transferring 
                 construction 
                 Low efficiency 
                 Xerox heater-in-pit 
               
               
                   
                 significant heat to 
                 No moving 
                 High temperatures 
                 1990 Hawkins et al 
               
               
                   
                 the aqueous ink. A 
                 parts 
                 required 
                 U.S. Pat. No. 4,899,181 
               
               
                   
                 bubble nucleates 
                 Fast operation 
                 High mechanical 
                 Hewlett-Packard TIJ 
               
               
                   
                 and quickly forms, 
                 Small chip area 
                 stress 
                 1982 Vaught et al 
               
               
                   
                 expelling the ink. 
                 required for 
                 Unusual materials 
                 U.S. Pat. No. 4,490,728 
               
               
                   
                 The efficiency of the 
                 actuator 
                 required 
               
               
                   
                 process is low, with 
                   
                 Large drive 
               
               
                   
                 typically less than 
                   
                 transistors 
               
               
                   
                 0.05% of the 
                   
                 Cavitation causes 
               
               
                   
                 electrical energy 
                   
                 actuator failure 
               
               
                   
                 being transformed 
                   
                 Kogation reduces 
               
               
                   
                 into kinetic energy 
                   
                 bubble formation 
               
               
                   
                 of the drop. 
                   
                 Large print heads 
               
               
                   
                   
                   
                 are difficult to 
               
               
                   
                   
                   
                 fabricate 
               
               
                 Piezo- 
                 A piezoelectric 
                 Low power 
                 Very large area 
                 Kyser et al 
               
               
                 electric 
                 crystal such as lead 
                 consumption 
                 required for 
                 U.S. Pat. No. 3,946,398 
               
               
                   
                 lanthanum zirconate 
                 Many ink types 
                 actuator 
                 Zoltan 
               
               
                   
                 (PZT) is electrically 
                 can be used 
                 Difficult to 
                 U.S. Pat. No. 3,683,212 
               
               
                   
                 activated, and either 
                 Fast operation 
                 integrate with 
                 1973 Stemme 
               
               
                   
                 expands, shears, or 
                 High efficiency 
                 electronics 
                 U.S. Pat. No.3,747,120 
               
               
                   
                 bends to apply 
                   
                 High voltage drive 
                 Epson Stylus 
               
               
                   
                 pressure to the ink, 
                   
                 transistors 
                 Tektronix IJ04 
               
               
                   
                 ejecting drops. 
                   
                 required 
               
               
                   
                   
                   
                 Full pagewidth 
               
               
                   
                   
                   
                 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, Usui et all 
               
               
                 strictive 
                 used to activate 
                 consumption 
                 strain (approx. 
                 JP 253401/96 
               
               
                   
                 electrostriction in 
                 Many ink types 
                 0.01%) 
                 IJ04 
               
               
                   
                 relaxor materials 
                 can be used 
                 Large area 
               
               
                   
                 such as lead 
                 Low thermal 
                 required for 
               
               
                   
                 lanthanum zirconate 
                 expansion 
                 actuator due to 
               
               
                   
                 titanate (PLZT) or 
                 Electric field 
                 low strain 
               
               
                   
                 lead magnesium 
                 strength 
                 Response speed is 
               
               
                   
                 niobate (PMN). 
                 required 
                 marginal (˜10 μs) 
               
               
                   
                   
                 (approx. 3.5 
                 High voltage drive 
               
               
                   
                   
                 V/μm) can be 
                 transistors 
               
               
                   
                   
                 generated 
                 required 
               
               
                   
                   
                 without 
                 Full pagewidth 
               
               
                   
                   
                 difficulty 
                 print heads 
               
               
                   
                   
                 Does not 
                 impractical due to 
               
               
                   
                   
                 require 
                 actuator size 
               
               
                   
                   
                 electrical poling 
               
               
                 Ferro- 
                 An electric field is 
                 Low power 
                 Difficult to 
                 IJ04 
               
               
                 electric 
                 used to induce a 
                 consumption 
                 integrate with 
               
               
                   
                 phase transition 
                 Many ink types 
                 electronics 
               
               
                   
                 between the 
                 can be used 
                 Unusual materials 
               
               
                   
                 antiferroelectric 
                 Fast operation 
                 such as PLZSnT 
               
               
                   
                 (AFE) and 
                 (&lt;1 μs) 
                 are required 
               
               
                   
                 ferroelectric (FE) 
                 Relatively high 
                 Actuators require 
               
               
                   
                 phase. Perovskite 
                 longitudinal 
                 a large area 
               
               
                   
                 materials such as tin 
                 strain 
               
               
                   
                 modified lead 
                 High efficiency 
               
               
                   
                 lanthanum zirconate 
                 Electric field 
               
               
                   
                 titanate (PLZSnT) 
                 strength of 
               
               
                   
                 exhibit large strains 
                 around 3 V/μm 
               
               
                   
                 of up to 1% 
                 can be readily 
               
               
                   
                 associated with the 
                 provided 
               
               
                   
                 AFE to FE phase 
               
               
                   
                 transition. 
               
               
                 Electro- 
                 Conductive plates 
                 Low power 
                 Difficult to 
                 IJ02, IJ04 
               
               
                 static 
                 are separated by a 
                 consumption 
                 operate 
               
               
                 plates 
                 compressible or 
                 Many ink types 
                 electrostatic 
               
               
                   
                 fluid dielectric 
                 can be used 
                 devices in an 
               
               
                   
                 (usually air). Upon 
                 Fast operation 
                 aqueous 
               
               
                   
                 application of a 
                   
                 environment 
               
               
                   
                 voltage, the plates 
                   
                 The electrostatic 
               
               
                   
                 attract each other 
                   
                 actuator will 
               
               
                   
                 and displace ink, 
                   
                 normally need to 
               
               
                   
                 causing drop 
                   
                 be separated from 
               
               
                   
                 ejection. The 
                   
                 the ink 
               
               
                   
                 conductive plates 
                   
                 Very large area 
               
               
                   
                 may be in a comb or 
                   
                 required to 
               
               
                   
                 honeycomb 
                   
                 achieve high 
               
               
                   
                 structure, or stacked 
                   
                 forces 
               
               
                   
                 to increase the 
                   
                 High voltage drive 
               
               
                   
                 surface area and 
                   
                 transistors may be 
               
               
                   
                 therefore the force. 
                   
                 required 
               
               
                   
                   
                   
                 Full pagewidth 
               
               
                   
                   
                   
                 print heads are not 
               
               
                   
                   
                   
                 competitive due to 
               
               
                   
                   
                   
                 actuator size 
               
               
                 Electro- 
                 A strong electric 
                 Low current 
                 High voltage 
                 1989 Saito et al, U.S. Pat. No. 
               
               
                 static pull 
                 field is applied to 
                 consumption 
                 required 
                 4,799,068 
               
               
                 on ink 
                 the ink, whereupon 
                 Low 
                 May be damaged 
                 1989 Miura et al, 
               
               
                   
                 electrostatic 
                 temperature 
                 by sparks due to 
                 U.S. Pat. No. 4,810,954 
               
               
                   
                 attraction 
                   
                 air breakdown 
                 Tone-jet 
               
               
                   
                 accelerates the ink 
                   
                 Required field 
               
               
                   
                 towards the print 
                   
                 strength increases 
               
               
                   
                 medium. 
                   
                 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 
                 Fast operation 
                 such as 
               
               
                   
                 ejection. Rare earth 
                 High efficiency 
                 Neodymium Iron 
               
               
                   
                 magnets with a field 
                 Easy extension 
                 Boron (NdFeB) 
               
               
                   
                 strength around 1 
                 from single 
                 required. 
               
               
                   
                 Tesla can be used. 
                 nozzles to 
                 High local 
               
               
                   
                 Examples are: 
                 pagewidth print 
                 currents required 
               
               
                   
                 Samarium Cobalt 
                 heads 
                 Copper 
               
               
                   
                 (SaCo) and 
                   
                 metalization 
               
               
                   
                 magnetic materials 
                   
                 should be used for 
               
               
                   
                 in the neodymium 
                   
                 long 
               
               
                   
                 iron boron family 
                   
                 electromigration 
               
               
                   
                 (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 
                 Low power 
                 Complex 
                 IJ01, IJ05, IJ08, 
               
               
                 magnetic 
                 a magnetic field in a 
                 consumption 
                 fabrication 
                 IJ10, IJ12, IJ14, 
               
               
                 core 
                 soft magnetic core 
                 Many ink types 
                 Materials not 
                 IJ15. IJ17 
               
               
                 electro- 
                 or yoke fabricated 
                 can be used 
                 usually present in 
               
               
                 magnetic 
                 from a ferrous 
                 Fast operation 
                 a CMOS fab such 
               
               
                   
                 material such as 
                 High efficiency 
                 as NiFe, CoNiFe, 
               
               
                   
                 electroplated iron 
                 Easy extension 
                 or CoFe are 
               
               
                   
                 alloys such as 
                 from single 
                 required 
               
               
                   
                 CoNiFe [1], CoFe, 
                 nozzles to 
                 High local 
               
               
                   
                 or NiFe alloys. 
                 pagewidth print 
                 currents required 
               
               
                   
                 Typically, the soft 
                 heads 
                 Copper 
               
               
                   
                 magnetic material is 
                   
                 metalization 
               
               
                   
                 in two parts, which 
                   
                 should be used for 
               
               
                   
                 are normally held 
                   
                 long 
               
               
                   
                 apart by a spring. 
                   
                 electromigration 
               
               
                   
                 when the solenoid 
                   
                 lifetime and low 
               
               
                   
                 is actuated, the two 
                   
                 resistivity 
               
               
                   
                 parts attract, 
                   
                 Electroplating is 
               
               
                   
                 displacing the 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 
                 from single 
                 High local 
               
               
                   
                 to the print head, for 
                 nozzles to 
                 currents required 
               
               
                   
                 example with rare 
                 pagewidth print 
                 Copper 
               
               
                   
                 earth permanent 
                 heads 
                 metalization 
               
               
                   
                 magnets. 
                   
                 should be used for 
               
               
                   
                 Only the current 
                   
                 long 
               
               
                   
                 carrying wire need 
                   
                 electromigration 
               
               
                   
                 be fabricated on the 
                   
                 lifetime and low 
               
               
                   
                 print-head, 
                   
                 resistivity 
               
               
                   
                 simplifying 
                   
                 Pigmented inks 
               
               
                   
                 materials 
                   
                 are usually 
               
               
                   
                 requirements. 
                   
                 infeasible 
               
               
                 Magneto- 
                 The actuator uses 
                 Many ink types 
                 Force acts as a 
                 Fischenbeck, U.S. Pat. No. 
               
               
                 striction 
                 the giant 
                 can be used 
                 twisting motion 
                 4,032,929 
               
               
                   
                 magnetostrictive 
                 Fast operation 
                 Unusual materials 
                 IJ25 
               
               
                   
                 effect of materials 
                 Easy extension 
                 such as Terfenol- 
               
               
                   
                 such as Terfenol-D 
                 from single 
                 D are required 
               
               
                   
                 (an alloy of terbium, 
                 nozzles to 
                 High local 
               
               
                   
                 dysprosium and iron 
                 pagewidth print 
                 currents required 
               
               
                   
                 developed at the 
                 heads 
                 Copper 
               
               
                   
                 Naval Ordnance 
                 High force is 
                 metalization 
               
               
                   
                 Laboratory, hence 
                 available 
                 should be used for 
               
               
                   
                 Ter-Fe-NOL). For 
                   
                 long 
               
               
                   
                 best efficiency, the 
                   
                 electromigration 
               
               
                   
                 actuator should be 
                   
                 lifetime and low 
               
               
                   
                 pre-stressed to 
                   
                 resistivity 
               
               
                   
                 approx. 8 MPa. 
                   
                 Pre-stressing may 
               
               
                   
                   
                   
                 be required 
               
               
                 Surface 
                 Ink under positive 
                 Low power 
                 Requires 
                 Silverbrook, EP 0771 658 A2 
               
               
                 tension 
                 pressure is held in a 
                 consumption 
                 supplementary 
                 and related 
               
               
                 reduction 
                 nozzle by surface 
                 Simple 
                 force to effect 
                 patent applications 
               
               
                   
                 tension. The surface 
                 construction 
                 drop separation 
               
               
                   
                 tension of the ink is 
                 No unusual 
                 Requires special 
               
               
                   
                 reduced below the 
                 materials 
                 ink surfactants 
               
               
                   
                 bubble threshold, 
                 required in 
                 Speed may be 
               
               
                   
                 causing the ink to 
                 fabrication 
                 limited by 
               
               
                   
                 egress from the 
                 High efficiency 
                 surfactant 
               
               
                   
                 nozzle. 
                 Easy extension 
                 properties 
               
               
                   
                   
                 from single 
               
               
                   
                   
                 nozzles to 
               
               
                   
                   
                 pagewidth print 
               
               
                   
                   
                 heads 
               
               
                 Viscosity 
                 The ink viscosity is 
                 Simple 
                 Requires 
                 Silverbrook, EP 0771 658 A2 
               
               
                 reduction 
                 locally reduced to 
                 construction 
                 supplementary 
                 and related 
               
               
                   
                 select which drops 
                 No unusual 
                 force to effect 
                 patent applications 
               
               
                   
                 are to be ejected. A 
                 materials 
                 drop separation 
               
               
                   
                 viscosity reduction 
                 required in 
                 Requires special 
               
               
                   
                 can be achieved 
                 fabrication 
                 ink viscosity 
               
               
                   
                 electrothermally 
                 Easy extension 
                 properties 
               
               
                   
                 with most inks, but 
                 from single 
                 High speed is 
               
               
                   
                 special inks can be 
                 nozzles to 
                 difficult to achieve 
               
               
                   
                 engineered for a 
                 pagewidth print 
                 Requires 
               
               
                   
                 100:1 viscosity 
                 heads 
                 oscillating ink 
               
               
                   
                 reduction. 
                   
                 pressure 
               
               
                   
                   
                   
                 A high 
               
               
                   
                   
                   
                 temperature 
               
               
                   
                   
                   
                 difference 
               
               
                   
                   
                   
                 (typically 80 
               
               
                   
                   
                   
                 degrees) is 
               
               
                   
                   
                   
                 required 
               
               
                 Acoustic 
                 An acoustic wave is 
                 Can operate 
                 Complex drive 
                 1993 Hadimioglu et al, 
               
               
                   
                 generated and 
                 without a nozzle 
                 circuitry 
                 EUP 550,192 
               
               
                   
                 focussed upon the 
                 plate 
                 Complex 
                 1993 Elrod et al, EUP 
               
               
                   
                 drop ejection region. 
                   
                 fabrication 
                 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 
                 relies upon 
                 consumption 
                 operation requires 
                 IJ18, IJ19, IJ20, 
               
               
                 bend 
                 differential thermal 
                 Many ink types 
                 a thermal insulator 
                 IJ21, IJ22, IJ23, 
               
               
                 actuator 
                 expansion upon 
                 can be used 
                 on the hot side 
                 IJ24, IJ27, IJ28, 
               
               
                   
                 Joule heating is 
                 Simple planar 
                 Corrosion 
                 IJ29, IJ30, IJ31, 
               
               
                   
                 used. 
                 fabrication 
                 prevention can be 
                 IJ32, IJ33, IJ34, 
               
               
                   
                   
                 Small chip area 
                 difficult 
                 IJ35, IJ36, IJ37, 
               
               
                   
                   
                 required for 
                 Pigmented inks 
                 IJ38, IJ39, IJ40, 
               
               
                   
                   
                 each actuator 
                 may be infeasible, 
                 IJ41 
               
               
                   
                   
                 Fast operation 
                 as pigment 
               
               
                   
                   
                 High efficiency 
                 particles may jam 
               
               
                   
                   
                 CMOS 
                 the bend actuator 
               
               
                   
                   
                 compatible 
               
               
                   
                   
                 voltages and 
               
               
                   
                   
                 currents 
               
               
                   
                   
                 Standard 
               
               
                   
                   
                 MEMS 
               
               
                   
                   
                 processes can 
               
               
                   
                   
                 be used 
               
               
                   
                   
                 Easy extension 
               
               
                   
                   
                 from single 
               
               
                   
                   
                 nozzles to 
               
               
                   
                   
                 pagewidth print 
               
               
                   
                   
                 heads 
               
               
                 High CTE 
                 A material with a 
                 High force can be 
                 Requires special 
                 IJ09, IJ17, IJ18, 
               
               
                 thermo- 
                 very high 
                 generated 
                 material (e.g. 
                 IJ20, IJ21, IJ22, 
               
               
                 elastic 
                 coefficient of thermal 
                 Three methods 
                 PTFE) 
                 IJ23, IJ24, IJ27, 
               
               
                 actuator 
                 expansion (CTE) 
                 of PTFE 
                 Requires a PTFE 
                 IJ28, IJ29, IJ30, 
               
               
                   
                 such as 
                 deposition are 
                 deposition 
                 IJ31, IJ42, IJ43, 
               
               
                   
                 polytetrafluoroethyl- 
                 under 
                 process, which is 
                 IJ44 
               
               
                   
                 ene (PTFE) is used. 
                 development: 
                 not yet standard in 
               
               
                   
                 As high CTE 
                 chemical vapor 
                 ULSI fabs 
               
               
                   
                 materials are usually 
                 deposition 
                 PTFE deposition 
               
               
                   
                 non-conductive, a 
                 (CVD), spin 
                 cannot be 
               
               
                   
                 heater fabricated 
                 coating, and 
                 followed with 
               
               
                   
                 from a conductive 
                 evaporation 
                 high temperature 
               
               
                   
                 material is 
                 PTFE is a 
                 (above 350° C.) 
               
               
                   
                 incorporated. A 50 
                 candidate for 
                 processing 
               
               
                   
                 μm long PTFE bend 
                 low dielectric 
                 Pigmented inks 
               
               
                   
                 actuator with 
                 constant 
                 may be infeasible, 
               
               
                   
                 polysilicon heater 
                 insulation in 
                 as pigment 
               
               
                   
                 and 15 mW power 
                 ULSI 
                 particles may jam 
               
               
                   
                 input can provide 
                 Very low power 
                 the bend actuator 
               
               
                   
                 180 μN force and 10 
                 consumption 
               
               
                   
                 μm deflection. 
                 Many ink types 
               
               
                   
                 Actuator motions 
                 can be used 
               
               
                   
                 include: 
                 Simple planar 
               
               
                   
                 Bend 
                 fabrication 
               
               
                   
                 Push 
                 Small chip area 
               
               
                   
                 Buckle 
                 required for 
               
               
                   
                 Rotate 
                 each actuator 
               
               
                   
                   
                 Fast operation 
               
               
                   
                   
                 High efficiency 
               
               
                   
                   
                 CMOS 
               
               
                   
                   
                 compatible 
               
               
                   
                   
                 voltages and 
               
               
                   
                   
                 currents 
               
               
                   
                   
                 Easy extension 
               
               
                   
                   
                 from single 
               
               
                   
                   
                 nozzles to 
               
               
                   
                   
                 pagewidth print 
               
               
                   
                   
                 heads 
               
               
                 Conduct- 
                 A polymer with a 
                 High force can 
                 Requires special 
                 IJ24 
               
               
                 ive 
                 high coefficient of 
                 be generated 
                 materials 
               
               
                 polymer 
                 thermal expansion 
                 Very low power 
                 development 
               
               
                 thermo- 
                 (such as PTFE) is 
                 consumption 
                 (High CTh 
               
               
                 elastic 
                 doped with 
                 Many ink types 
                 conductive 
               
               
                 actuator 
                 conducting 
                 can be used 
                 polymer) 
               
               
                   
                 substances to 
                 Simple planar 
                 Requires a PTFE 
               
               
                   
                 increase its 
                 fabrication 
                 deposition 
               
               
                   
                 conductivity to 
                 Small chip area 
                 process, which is 
               
               
                   
                 about 3 orders of 
                 required for 
                 not yet standard in 
               
               
                   
                 magnitude below 
                 each actuator 
                 ULSI fabs 
               
               
                   
                 that of copper. The 
                 Fast operation 
                 PTFE deposition 
               
               
                   
                 conducting polymer 
                 High efficiency 
                 cannot be 
               
               
                   
                 expands when 
                 CMOS 
                 followed with 
               
               
                   
                 resistively heated. 
                 compatible 
                 high temperature 
               
               
                   
                 Examples of 
                 voltages and currents 
                 (above 350° C.) 
               
               
                   
                 conducting dopants 
                 Easy extension 
                 processing 
               
               
                   
                 include: 
                 from single 
                 Evaporation and 
               
               
                   
                 Carbon nanotubes 
                 nozzles to 
                 CVD deposition 
               
               
                   
                 Metal fibers 
                 pagewidth print 
                 techniques cannot 
               
               
                   
                 Conductive 
                 heads 
                 be used 
               
               
                   
                 polymers such as 
                   
                 Pigmented inks 
               
               
                   
                 doped 
                   
                 may be infeasibie, 
               
               
                   
                 polythiophene 
                   
                 as pigment 
               
               
                   
                 Carbon granules 
                   
                 particles may jam 
               
               
                   
                   
                   
                 the bend actuator 
               
               
                 Shape 
                 A shape memory 
                 High force is 
                 Fatigue limits 
                 IJ26 
               
               
                 memory 
                 alloy such as TiNi 
                 available 
                 maximum number 
               
               
                 alloy 
                 (also known as 
                 (stresses of 
                 of cycles 
               
               
                   
                 Nitinol - Nickel 
                 hundreds of 
                 Low strain (1%) is 
               
               
                   
                 Titanium ailoy 
                 MPa) 
                 required to extend 
               
               
                   
                 developed at the 
                 Large strain is 
                 fatigue resistance 
               
               
                   
                 Naval Ordnance 
                 available (more 
                 Cycle rate limited 
               
               
                   
                 Laboratory) is 
                 than 3%) 
                 by heat removal 
               
               
                   
                 thermally switched 
                 High corrosion 
                 Requires unusual 
               
               
                   
                 between its weak 
                 resistance 
                 materials (TiNi) 
               
               
                   
                 martensitic state and 
                 Simple 
                 The latent heat of 
               
               
                   
                 its high stiffness 
                 construction 
                 transformation 
               
               
                   
                 austenic state. The 
                 Easy extension 
                 must be provided 
               
               
                   
                 shape of the actuator 
                 from single 
                 High current 
               
               
                   
                 in its martensitic 
                 nozzles to 
                 operation 
               
               
                   
                 state is deformed 
                 pagewidth print 
                 Requires pre- 
               
               
                   
                 relative to the 
                 heads 
                 stressing to distort 
               
               
                   
                 austenic shape. The 
                 Low voltage 
                 the martensitic 
               
               
                   
                 shape change causes 
                 operation 
                 state 
               
               
                   
                 ejection of a drop. 
               
               
                 Linear 
                 Linear magnetic 
                 Linear Magnetic 
                 Requires unusual 
                 IJ12 
               
               
                 Magnetic 
                 actuators include the 
                 actuators can he 
                 semiconductor 
               
               
                 Actuator 
                 Linear Induction 
                 constructed with 
                 materials such as 
               
               
                   
                 Actuator (LIA), 
                 high thrust, long 
                 soft magnetic 
               
               
                   
                 Linear Permanent 
                 travel, and high 
                 alloys (e.g. 
               
               
                   
                 Magnet 
                 efficiency using 
                 CoNiFe) 
               
               
                   
                 Synchronous 
                 planar 
                 Some varieties 
               
               
                   
                 Actuator (LPMSA), 
                 semiconductor 
                 also require 
               
               
                   
                 Linear Reluctance 
                 fabrication 
                 permanent 
               
               
                   
                 Synchronous 
                 techniques 
                 magnetic 
               
               
                   
                 Actuator (LRSA), 
                 Long actuator 
                 materials such as 
               
               
                   
                 Linear Switched 
                 travel is 
                 Neodymium iron 
               
               
                   
                 Reluctance Actuator 
                 available 
                 boron (NdFeB) 
               
               
                   
                 (LSRA), and the 
                 Medium force is 
                 Requires complex 
               
               
                   
                 Linear Stepper 
                 available 
                 multi-phase drive 
               
               
                   
                 Actuator (LSA). 
                 Low voltage 
                 circuitry 
               
               
                   
                   
                 operation 
                 High current 
               
               
                   
                   
                   
                 operation 
               
            
           
           
               
            
               
                 Basic operation mode 
               
            
           
           
               
               
               
               
               
            
               
                 Actuator 
                 This is the simplest 
                 Simple 
                 Drop repetition 
                 Thermal ink jet 
               
               
                 directly 
                 mode of operation: 
                 operation 
                 rate is usually 
                 Piezoelectric ink jet 
               
               
                 pushes ink 
                 the actuator directly 
                 No external 
                 limited to around 
                 IJ01. IJ02, IJ03, 
               
               
                   
                 supplies sufficient 
                 fields required 
                 10 kHz. 
                 IJ04, IJ05, IJ06, 
               
               
                   
                 kinetic energy to 
                 Satellite drops 
                 However, this is 
                 IJ07, IJ09, IJ11, 
               
               
                   
                 expel the drop. The 
                 can be avoided 
                 not fundamental 
                 IJ12, IJ14, IJ16, 
               
               
                   
                 drop must have a 
                 if drop velocity 
                 to the method, 
                 IJ20, IJ22, IJ23, 
               
               
                   
                 sufficient velocity to 
                 is less than 4 
                 but is related to 
                 IJ24, IJ25, IJ26, 
               
               
                   
                 overcome the 
                 m/s 
                 the refill method 
                 IJ27, IJ28, IJ29, 
               
               
                   
                 surface tension. 
                 Can be efficient, 
                 normally used 
                 IJ30, IJ31, IJ32, 
               
               
                   
                   
                 depending upon 
                 All of the drop 
                 IJ33, IJ34, IJ35, 
               
               
                   
                   
                 the actuator 
                 kinetic energy 
                 IJ36, IJ37, IJ38, 
               
               
                   
                   
                 used 
                 must be provided 
                 IJ39, IJ40, IJ41, 
               
               
                   
                   
                   
                 by the actuator 
                 IJ42, IJ43, IJ44 
               
               
                   
                   
                   
                 Satellite drops 
               
               
                   
                   
                   
                 usually form if 
               
               
                   
                   
                   
                 drop velocity is 
               
               
                   
                   
                   
                 greater than 4.5 
               
               
                   
                   
                   
                 m/s 
               
               
                 Proximity 
                 The drops to be 
                 Very simple 
                 Requires close 
                 Silverbrook, EP 0771 658 A2 
               
               
                   
                 printed are selected 
                 print head 
                 proximity 
                 and related 
               
               
                   
                 by some manner 
                 fabrication can 
                 between the print 
                 patent applications 
               
               
                   
                 (e.g. thermally 
                 be used 
                 head and the 
               
               
                   
                 induced surface 
                 The drop 
                 print media or 
               
               
                   
                 tension reduction of 
                 selection means 
                 transfer roller 
               
               
                   
                 pressurized ink). 
                 does not need to 
                 May require two 
               
               
                   
                 Selected drops are 
                 provide the 
                 print heads 
               
               
                   
                 separated from the 
                 energy required 
                 printing alternate 
               
               
                   
                 ink in the nozzle by 
                 to separate the 
                 rows of the 
               
               
                   
                 contact with the 
                 drop from the 
                 image 
               
               
                   
                 print medium or a 
                 nozzle 
                 Monolithic color 
               
               
                   
                 transfer roller. 
                   
                 print heads are 
               
               
                   
                   
                   
                 difficult 
               
               
                 Electro- 
                 The drops to be 
                 Very simple 
                 Requires very 
                 Silverbrook, EP 0771 658 A2 
               
               
                 static pull 
                 printed are selected 
                 print head 
                 high electrostatic 
                 and related 
               
               
                 on ink 
                 by some manner 
                 fabrication can 
                 field 
                 patent applications 
               
               
                   
                 (e.g. thermally 
                 be used 
                 Electrostatic field 
                 Tone-Jet 
               
               
                   
                 induced surface 
                 The drop 
                 for small nozzle 
               
               
                   
                 tension reduction of 
                 selection means 
                 sizes is above air 
               
               
                   
                 pressurized ink). 
                 does not need to 
                 breakdown 
               
               
                   
                 Selected drops are 
                 provide the 
                 Electrostatic field 
               
               
                   
                 separated from the 
                 energy required 
                 may attract dust 
               
               
                   
                 ink in the nozzle by 
                 to separate the 
               
               
                   
                 a strong electric 
                 drop from the 
               
               
                   
                 field. 
                 nozzle 
               
               
                 Magnetic 
                 The drops to be 
                 Very simpie 
                 Requires 
                 Silverbrook, EP 0771 658 A2 
               
               
                 pull on ink 
                 printed are selected 
                 print head 
                 magnetic ink 
                 and related 
               
               
                   
                 by some manner 
                 fabrication can 
                 Ink colors other 
                 patent applications 
               
               
                   
                 (e.g. thermally 
                 be used 
                 than black are 
               
               
                   
                 induced surface 
                 The drop 
                 difficult 
               
               
                   
                 tension reduction of 
                 selection means 
                 Requires very 
               
               
                   
                 pressurized ink). 
                 does not need to 
                 high magnetic 
               
               
                   
                 Selected drops are 
                 provide the 
                 fields 
               
               
                   
                 separated from the 
                 energy required 
               
               
                   
                 ink in the nozzle by 
                 to separate the 
               
               
                   
                 a strong magnetic 
                 drop from the 
               
               
                   
                 field acting on the 
                 nozzle 
               
               
                   
                 magnetic ink. 
               
               
                 Shutter 
                 The actuator moves 
                 High speed 
                 Moving parts are 
                 IJ13, IJ17, IJ21 
               
               
                   
                 a shutter to block 
                 (&gt;50 kHz) 
                 required 
               
               
                   
                 ink flow to the 
                 operation can be 
                 Requires ink 
               
               
                   
                 nozzle. The ink 
                 achieved due to 
                 pressure 
               
               
                   
                 pressure is pulsed at 
                 reduced refill 
                 modulator 
               
               
                   
                 a multiple of the 
                 time 
                 Friction and wear 
               
               
                   
                 drop ejection 
                 Drop timing can 
                 must be 
               
               
                   
                 frequency. 
                 be very accurate 
                 considered 
               
               
                   
                   
                 The actuator 
                 Stiction is 
               
               
                   
                   
                 energy can be 
                 possible 
               
               
                   
                   
                 very low 
               
               
                 Shuttered 
                 The actuator moves 
                 Actuators with 
                 Moving parts are 
                 IJ08, IJ15, IJ18, 
               
               
                 grill 
                 a shutter to block 
                 small travel can 
                 required 
                 IJ19 
               
               
                   
                 ink flow through a 
                 be used 
                 Requires ink 
               
               
                   
                 grill to the nozzle. 
                 Actuators with 
                 pressure 
               
               
                   
                 The shutter 
                 small force can 
                 modulator 
               
               
                   
                 movement need 
                 be used 
                 Friction and wear 
               
               
                   
                 only be equal to the 
                 High speed 
                 must be 
               
               
                   
                 width of the grill 
                 (&gt;50 kHz) 
                 considered 
               
               
                   
                 holes. 
                 operation can be 
                 Stiction is 
               
               
                   
                   
                 achieved 
                 possible 
               
               
                 Pulsed 
                 A pulsed magnetic 
                 Extremely low 
                 Requires an 
                 IJ10 
               
               
                 magnetic 
                 field attracts an ‘ink 
                 energy 
                 external pulsed 
               
               
                 pull on ink 
                 pusher’ at the drop 
                 operation is 
                 magnetic field 
               
               
                 pusher 
                 ejection frequency. 
                 possible 
                 Requires special 
               
               
                   
                 An actuator controls 
                 No heat 
                 materials for both 
               
               
                   
                 a catch, which 
                 dissipation 
                 the actuator and 
               
               
                   
                 prevents the ink 
                 problems 
                 the ink pusher 
               
               
                   
                 pusher from moving 
                   
                 Complex 
               
               
                   
                 when a drop is not 
                   
                 construction 
               
               
                   
                 to be ejected. 
               
            
           
           
               
            
               
                 Auxiliary mechanism (applied to all nozzles) 
               
            
           
           
               
               
               
               
               
            
               
                 None 
                 The actuator directly 
                 Simplicity of 
                 Drop ejection 
                 Most ink jets, including 
               
               
                   
                 fires the ink drop, 
                 construction 
                 energy must be 
                 piezoelectric and thermal 
               
               
                   
                 and there is no 
                 Simplicity of 
                 supplied by 
                 bubble. 
               
               
                   
                 external field or 
                 operation 
                 individual nozzle 
                 IJ01, IJ02, IJ03, 
               
               
                   
                 other mechanism 
                 Small physical 
                 actuator 
                 IJ04, IJ05, IJ07, 
               
               
                   
                 required. 
                 size 
                   
                 IJ09, IJ11, IJ12, 
               
               
                   
                   
                   
                   
                 IJ14, IJ20, IJ22, 
               
               
                   
                   
                   
                   
                 IJ23, IJ24, IJ25, 
               
               
                   
                   
                   
                   
                 IJ26, IJ27, IJ28, 
               
               
                   
                   
                   
                   
                 IJ29, IJ30, IJ31, 
               
               
                   
                   
                   
                   
                 IJ32, IJ33, IJ34, 
               
               
                   
                   
                   
                   
                 IJ35, IJ36, IJ37, 
               
               
                   
                   
                   
                   
                 IJ38, IJ39, IJ40, 
               
               
                   
                   
                   
                   
                 IJ41, IJ42, IJ43, 
               
               
                   
                   
                   
                   
                 IJ44 
               
               
                 Oscillating 
                 The ink pressure 
                 Oscillating ink 
                 Requires external 
                 Silverbrook, EP 0771 658 A2 
               
               
                 ink 
                 oscillates, providing 
                 pressure can 
                 ink pressure 
                 and related 
               
               
                 pressure 
                 much of the drop 
                 provide a refill 
                 osciilator 
                 patent applications 
               
               
                 (including 
                 ejection energy. The 
                 pulse, allowing 
                 Ink pressure 
                 IJ08, IJ13, IJ15, 
               
               
                 acoustic 
                 actuator selects 
                 higher operating 
                 phase and 
                 IJ17, IJ18, IJ19, 
               
               
                 stimu- 
                 which drops are to 
                 speed 
                 amplitude must 
                 IJ21 
               
               
                 lation) 
                 be fired by 
                 The actuators 
                 be carefully 
               
               
                   
                 selectively blocking 
                 may operate 
                 controlled 
               
               
                   
                 or enabling nozzles. 
                 with much 
                 Acoustic 
               
               
                   
                 The ink pressure 
                 lower energy 
                 reflections in the 
               
               
                   
                 oscillation may be 
                 Acoustic lenses 
                 ink chamber 
               
               
                   
                 achieved by 
                 can be used to 
                 must be designed 
               
               
                   
                 vibrating the print 
                 focus the sound 
                 for 
               
               
                   
                 head, or preferably 
                 on the nozzles 
               
               
                   
                 by an actuator in the 
               
               
                   
                 ink supply. 
               
               
                 Media 
                 The print head is 
                 Low power 
                 Precision 
                 Silverbrook, EP 0771 658 A2 
               
               
                 proximity 
                 placed in close 
                 High accuracy 
                 assembly 
                 and related 
               
               
                   
                 proximity to the 
                 Simple print 
                 required 
                 patent applications 
               
               
                   
                 print medium. 
                 head 
                 Paper fibers may 
               
               
                   
                 Selected drops 
                 construction 
                 cause problems 
               
               
                   
                 protrude from the 
                   
                 Cannot print on 
               
               
                   
                 print head further 
                   
                 rough substrates 
               
               
                   
                 than unselected 
               
               
                   
                 drops, and contact 
               
               
                   
                 the print medium. 
               
               
                   
                 The drop soaks into 
               
               
                   
                 the medium fast 
               
               
                   
                 enough to cause 
               
               
                   
                 drop separation. 
               
               
                 Transfer 
                 Drops are printed to 
                 High accuracy 
                 Bulky 
                 Silverbrook, EP 0771 658 A2 
               
               
                 roller 
                 a transfer roller 
                 Wide range of 
                 Expensive 
                 and related 
               
               
                   
                 instead of straight to 
                 print substrates 
                 Complex 
                 patent applications 
               
               
                   
                 the print medium. A 
                 can be used 
                 construction 
                 Tektronix hot melt 
               
               
                   
                 transfer roller can 
                 Ink can be dried 
                   
                 piezoelectric ink jet 
               
               
                   
                 also be used for 
                 on the transfer 
                   
                 Any of the IJ series 
               
               
                   
                 proximity drop 
                 roller 
               
               
                   
                 separation. 
               
               
                 Electro- 
                 An electric field is 
                 Low power 
                 Field strength 
                 Silverbrook, EP 0771 658 A2 
               
               
                 static 
                 used to accelerate 
                 Simple pnnt 
                 required for 
                 and related 
               
               
                   
                 selected drops 
                 head 
                 separation of 
                 patent applications 
               
               
                   
                 towards the print 
                 construction 
                 small drops is 
                 Tone-Jet 
               
               
                   
                 medium. 
                   
                 near or above air 
               
               
                   
                   
                   
                 breakdown 
               
               
                 Direct 
                 A magnetic field is 
                 Low power 
                 Requires 
                 Silverbrook, EP 0771 658 A2 
               
               
                 magnetic 
                 used to accelerate 
                 Simple print 
                 magnetic ink 
                 and related 
               
               
                 field 
                 selected drops of 
                 head 
                 Requires strong 
                 patent applications 
               
               
                   
                 magnetic ink 
                 construction 
                 magnetic field 
               
               
                   
                 towards the print 
               
               
                   
                 medium. 
               
               
                 Cross 
                 The print head is 
                 Does not 
                 Requires external 
                 IJ06, IJ16 
               
               
                 magnetic 
                 placed in a constant 
                 require 
                 magnet 
               
               
                 field 
                 magnetic field. The 
                 magnetic 
                 Current densities 
               
               
                   
                 Lorenz force in a 
                 materials to be 
                 may be high, 
               
               
                   
                 current carrying 
                 integrated in the 
                 resulting in 
               
               
                   
                 wire is used to move 
                 print head 
                 electromigration 
               
               
                   
                 the actuator. 
                 manufacturing 
                 problems 
               
               
                   
                 process 
               
               
                 Pulsed 
                 A pulsed magnetic 
                 Very low power 
                 Complex print 
                 IJ10 
               
               
                 magnetic 
                 field is used to 
                 operation is 
                 head construction 
               
               
                 field 
                 cyclically attract a 
                 possible 
                 Magnetic 
               
               
                   
                 paddle, which 
                 Small print head 
                 materials 
               
               
                   
                 pushes on the ink. A 
                 size 
                 required in print 
               
               
                   
                 small actuator 
                   
                 head 
               
               
                   
                 moves a catch, 
               
               
                   
                 which selectively 
               
               
                   
                 prevents the paddle 
               
               
                   
                 from moving. 
               
            
           
           
               
            
               
                 Actuator amplification or modification method 
               
            
           
           
               
               
               
               
               
            
               
                 None 
                 No actuator 
                 Operational 
                 Many actuator 
                 Thermal Bubble Ink jet 
               
               
                   
                 mechanical 
                 simplicity 
                 mechanisms 
                 IJ01, IJ02, IJ06, 
               
               
                   
                 amplification is 
                   
                 have 
                 IJ07, IJ16, IJ25, IJ26 
               
               
                   
                 used. The actuator 
                   
                 insufficient 
               
               
                   
                 directly drives the 
                   
                 travel, or 
               
               
                   
                 drop ejection 
                   
                 insufficient 
               
               
                   
                 process. 
                   
                 force, to 
               
               
                   
                   
                   
                 efficiently drive 
               
               
                   
                   
                   
                 the drop 
               
               
                   
                   
                   
                 ejection process 
               
               
                 Differential 
                 An actuator material 
                 Provides greater 
                 High stresses 
                 Piezoelectric 
               
               
                 expansion 
                 expands more on 
                 travel in a 
                 are involved 
                 IJ03, IJ09, IJ17, 
               
               
                 bend 
                 one side than on the 
                 reduced print 
                 Care must be 
                 IJ18, IJ19, IJ20, 
               
               
                 actuator 
                 other. The 
                 head area 
                 taken that the 
                 IJ21, IJ22, IJ23, 
               
               
                   
                 expansion may be 
                   
                 materials do not 
                 IJ24, IJ27, IJ29, 
               
               
                   
                 thermal, 
                   
                 delaminate 
                 IJ30, IJ31, IJ32, 
               
               
                   
                 piezoelectric, 
                   
                 Residual bend 
                 IJ33, IJ34, IJ35, 
               
               
                   
                 magnetostrictive, or 
                   
                 resulting from 
                 IJ36, IJ37, IJ38, 
               
               
                   
                 other mechanism. 
                   
                 high 
                 IJ39, IJ42, IJ43, 
               
               
                   
                 The bend actuator 
                   
                 temperature or 
                 IJ44 
               
               
                   
                 converts a high 
                   
                 high stress 
               
               
                   
                 force low travel 
                   
                 during 
               
               
                   
                 actuator mechanism 
                   
                 formation 
               
               
                   
                 to high travel, lower 
               
               
                   
                 force mechanism. 
               
               
                 Transient 
                 A trilayer bend 
                 Very good 
                 High stresses 
                 IJ40, IJ41 
               
               
                 bend 
                 actuator where the 
                 temperature 
                 are involved 
               
               
                 actuator 
                 two outside layers 
                 stability 
                 Care must be 
               
               
                   
                 are identical. This 
                 High speed, as a 
                 taken that the 
               
               
                   
                 cancels bend due to 
                 new drop can be 
                 materials do not 
               
               
                   
                 ambient temperature 
                 fired before heat 
                 delaminate 
               
               
                   
                 and residual stress. 
                 dissipates 
               
               
                   
                 The actuator only 
                 Cancels residual 
               
               
                   
                 responds to transient 
                 stress of 
               
               
                   
                 heating of one side 
                 formation 
               
               
                   
                 or the other. 
               
               
                 Reverse 
                 The actuator loads a 
                 Better coupling 
                 Fabrication 
                 IJ05, IJ11 
               
               
                 spring 
                 spring. When the 
                 to the ink 
                 complexity 
               
               
                   
                 actuator is turned 
                   
                 High stress in 
               
               
                   
                 off, the spring 
                   
                 the spring 
               
               
                   
                 releases. This can 
               
               
                   
                 reverse the 
               
               
                   
                 force/distance curve 
               
               
                   
                 of the actuator to 
               
               
                   
                 make it compatible 
               
               
                   
                 with the force/time 
               
               
                   
                 requirements of the 
               
               
                   
                 drop ejection. 
               
               
                 Actuator 
                 A series of thin 
                 Increased travel 
                 Increased 
                 Some piezoelectric ink 
               
               
                 stack 
                 actuators are 
                 Reduced drive 
                 fabrication 
                 jets 
               
               
                   
                 stacked. This can be 
                 voltage 
                 complexity 
                 IJ04 
               
               
                   
                 appropriate where 
                   
                 Increased 
               
               
                   
                 actuators require 
                   
                 possibility of 
               
               
                   
                 high electric field 
                   
                 short circuits 
               
               
                   
                 strength, such as 
                   
                 due to pinholes 
               
               
                   
                 electrostatic and 
               
               
                   
                 piezoelectric 
               
               
                   
                 actuators. 
               
               
                 Multiple 
                 Multiple smaller 
                 Increases the 
                 Actuator forces 
                 IJ12, IJ13, IJ18, 
               
               
                 actuators 
                 actuators are used 
                 force available 
                 may not add 
                 IJ20, IJ22, IJ28, 
               
               
                   
                 simultaneously to 
                 from an actuator 
                 linearly, 
                 IJ42, IJ43 
               
               
                   
                 move the ink. Each 
                 Multiple 
                 reducing 
               
               
                   
                 actuator need 
                 actuators can be 
                 efficiency 
               
               
                   
                 provide only a 
                 positioned to 
               
               
                   
                 portion of the force 
                 control ink flow 
               
               
                   
                 required. 
                 accurately 
               
               
                 Linear 
                 A linear spring is 
                 Matches low 
                 Requires print 
                 IJ15 
               
               
                 Spring 
                 used to transform a 
                 travel actuator 
                 head area for 
               
               
                   
                 motion with small 
                 with higher 
                 the spring 
               
               
                   
                 travel and high force 
                 travel 
               
               
                   
                 into a longer travel, 
                 requirements 
               
               
                   
                 lower force motion. 
                 Non-contact 
               
               
                   
                   
                 method of 
               
               
                   
                   
                 motion 
               
               
                   
                   
                 transformation 
               
               
                 Coiled 
                 A bend actuator is 
                 Increases travel 
                 Generally 
                 IJ17, IJ21, IJ34, 
               
               
                 actuator 
                 coiled to provide 
                 Reduces chip 
                 restricted to 
                 IJ35 
               
               
                   
                 greater travel in a 
                 area 
                 planar 
               
               
                   
                 reduced chip area. 
                 Planar 
                 implementations 
               
               
                   
                   
                 implementations 
                 due to extreme 
               
               
                   
                   
                 are relatively 
                 fabrication 
               
               
                   
                   
                 easy to 
                 difficulty in 
               
               
                   
                   
                 fabricate. 
                 other 
               
               
                   
                   
                   
                 orientations. 
               
               
                 Flexure 
                 A bend actuator has 
                 Simple means 
                 Care must be 
                 IJ10, IJ19, IJ33 
               
               
                 bend 
                 a small region near 
                 of increasing 
                 taken not to 
               
               
                 actuator 
                 the fixture point, 
                 travel of a bend 
                 exceed the 
               
               
                   
                 which flexes much 
                 actuator 
                 elastic limit in 
               
               
                   
                 more readily than 
                   
                 the flexure area 
               
               
                   
                 the remainder of the 
                   
                 Stress 
               
               
                   
                 actuator. The 
                   
                 distribution is 
               
               
                   
                 actuator flexing is 
                   
                 very uneven 
               
               
                   
                 effectively 
                   
                 Difficult to 
               
               
                   
                 converted from an 
                   
                 accurately 
               
               
                   
                 even coiling to an 
                   
                 model with 
               
               
                   
                 angular bend, 
                   
                 finite element 
               
               
                   
                 resulting in greater 
                   
                 analysis 
               
               
                   
                 travel of the actuator 
               
               
                   
                 tip. 
               
               
                 Catch 
                 The actuator 
                 Very low 
                 Complex 
                 IJ10 
               
               
                   
                 controls a small 
                 actuator energy 
                 construction 
               
               
                   
                 catch. The catch 
                 Very small 
                 Requires 
               
               
                   
                 either enables or 
                 actuator size 
                 external force 
               
               
                   
                 disables movement 
                   
                 Unsuitable for 
               
               
                   
                 of an ink pusher that 
                   
                 pigmented inks 
               
               
                   
                 is controlled in a 
               
               
                   
                 bulk manner. 
               
               
                 Gears 
                 Gears can be used to 
                 Low force, low 
                 Moving parts 
                 IJ13 
               
               
                   
                 increase travel at the 
                 travel actuators 
                 are required 
               
               
                   
                 expense of duration. 
                 can he used 
                 Several actuator 
               
               
                   
                 Circular gears, rack 
                 Can be 
                 cycles are 
               
               
                   
                 and pinion, ratchets, 
                 fabricated using 
                 required 
               
               
                   
                 and other gearing 
                 standard surface 
                 More complex 
               
               
                   
                 methods can be 
                 MEMS 
                 drive electronics 
               
               
                   
                 used. 
                 processes 
                 Complex 
               
               
                   
                   
                   
                 constrtiction 
               
               
                   
                   
                   
                 Friction, 
               
               
                   
                   
                   
                 friction, and 
               
               
                   
                   
                   
                 wear are 
               
               
                   
                   
                   
                 possible 
               
               
                 Buckle 
                 A buckle plate can 
                 Very fast 
                 Must stay 
                 S. Hirata et al, “An Ink-jet 
               
               
                 plate 
                 be used to change a 
                 movement 
                 within elastic 
                 Head Using Diaphragm 
               
               
                   
                 slow actuator into a 
                 achievable 
                 limits of the 
                 Microactuator”, Proc. 
               
               
                   
                 fast motion. It can 
                   
                 materials for 
                 IEEE MEMS, Feb. 1996, 
               
               
                   
                 also convert a high 
                   
                 long device life 
                 pp 418-423. 
               
               
                   
                 force, low travel 
                   
                 High stresses 
                 IJ18, IJ27 
               
               
                   
                 actuator into a high 
                   
                 involved 
               
               
                   
                 travel, medium force 
                   
                 Generally high 
               
               
                   
                 motion. 
                   
                 power 
               
               
                   
                   
                   
                 requirement 
               
               
                 Tapered 
                 A tapered magnetic 
                 Linearizes the 
                 Complex 
                 IJ14 
               
               
                 magnetic 
                 pole can increase 
                 magnetic 
                 construction 
               
               
                 pole 
                 travel at the expense 
                 force/distance 
               
               
                   
                 of force. 
                 curve 
               
               
                 Lever 
                 A lever and fulcrum 
                 Matches low 
                 High stress 
                 IJ32, IJ36, IJ37 
               
               
                   
                 is used to transform 
                 travel actuator 
                 around the 
               
               
                   
                 a motion with small 
                 with higher 
                 fulcrum 
               
               
                   
                 travel and high force 
                 travel 
               
               
                   
                 into a motion with 
                 requirements 
               
               
                   
                 longer travel and 
                 Fulcrum area 
               
               
                   
                 lower force. The 
                 has no linear 
               
               
                   
                 lever can also 
                 movement, and 
               
               
                   
                 reverse the direction 
                 can be used for 
               
               
                   
                 of travel. 
                 a fluid seal 
               
               
                 Rotary 
                 The actuator is 
                 High 
                 Complex 
                 IJ28 
               
               
                 impeller 
                 connected to a 
                 mechanical 
                 construction 
               
               
                   
                 rotary impeller. A 
                 advantage 
                 Unsuitable for 
               
               
                   
                 small angular 
                 The ratio of 
                 pigmented inks 
               
               
                   
                 deflection of the 
                 force to travel 
               
               
                   
                 actuator results in a 
                 of the actuator 
               
               
                   
                 rotation of the 
                 can be matched 
               
               
                   
                 impeller vanes, 
                 to the nozzle 
               
               
                   
                 which push the ink 
                 requirements by 
               
               
                   
                 against stationary 
                 varying the 
               
               
                   
                 vanes and out of the 
                 number of 
               
               
                   
                 nozzle. 
                 impeller vanes 
               
               
                 Acoustic 
                 A refractive or 
                 No moving 
                 Large area 
                 1993 Hadimioglu et al, 
               
               
                 lens 
                 diffractive (e.g. zone 
                 parts 
                 required 
                 EUP 550,192 
               
               
                   
                 plate) acoustic lens 
                   
                 Only relevant 
                 1993 Elrod et al, EUP 
               
               
                   
                 is used to 
                   
                 for acoustic ink 
                 572,220 
               
               
                   
                 concentrate sound 
                   
                 jets 
               
               
                   
                 waves. 
               
               
                 Sharp 
                 A sharp point is 
                 Simple 
                 Difficult to 
                 Tone-jet 
               
               
                 conductive 
                 used to concentrate 
                 construction 
                 fabricate using 
               
               
                 point 
                 an electrostatic field. 
                   
                 standard VLSI 
               
               
                   
                   
                   
                 processes for a 
               
               
                   
                   
                   
                 surface ejecting 
               
               
                   
                   
                   
                 ink-jet 
               
               
                   
                   
                   
                 Only relevant 
               
               
                   
                   
                   
                 for electrostatic 
               
               
                   
                   
                   
                 ink jets 
               
            
           
           
               
            
               
                 Actuator motion 
               
            
           
           
               
               
               
               
               
            
               
                 Volume 
                 The volume of the 
                 Simple 
                 High energy is 
                 Hewlett-Packard Thermal 
               
               
                 expansion 
                 actuator changes, 
                 construction in 
                 typically 
                 Ink jet 
               
               
                   
                 pushing the ink in 
                 the case of 
                 required to 
                 Canon Bubblejet 
               
               
                   
                 all directions. 
                 thermal ink jet 
                 achieve volume 
               
               
                   
                   
                   
                 expansion. This 
               
               
                   
                   
                   
                 leads to thermal 
               
               
                   
                   
                   
                 stress, 
               
               
                   
                   
                   
                 cavitation, and 
               
               
                   
                   
                   
                 kogation in 
               
               
                   
                   
                   
                 thermal ink jet 
               
               
                   
                   
                   
                 implementations 
               
               
                 Linear, 
                 The actuator moves 
                 Efficient 
                 High fabrication 
                 IJ01, IJ02, IJ04, 
               
               
                 normal to 
                 in a direction normal 
                 coupling to ink 
                 complexity may 
                 IJ07, IJ11, IJ14 
               
               
                 chip 
                 to the print head 
                 drops ejected 
                 be required to 
               
               
                 surface 
                 surface. The nozzle 
                 normal to the 
                 achieve 
               
               
                   
                 is typically in the 
                 surface 
                 perpendicular 
               
               
                   
                 line of movement. 
                   
                 motion 
               
               
                 Parallel to 
                 The actuator moves 
                 Suitable for 
                 Fabrication 
                 IJ12, IJ13, IJ15, 
               
               
                 chip 
                 parallel to the print 
                 planar 
                 complexity 
                 IJ33, IJ34, IJ35, 
               
               
                 surface 
                 head surface. Drop 
                 fabrication 
                 Friction 
                 IJ36 
               
               
                   
                 ejection may still be 
                   
                 Stiction 
               
               
                   
                 normal to the 
               
               
                   
                 surface. 
               
               
                 Membrane 
                 An actuator with a 
                 The effective 
                 Fabrication 
                 1982 Howkins U.S. Pat. No. 
               
               
                 push 
                 high force but small 
                 area of the 
                 complexity 
                 4,459,601 
               
               
                   
                 area is used to push 
                 actuator 
                 Actuator size 
               
               
                   
                 a stiff membrane 
                 becomes the 
                 Difficulty of 
               
               
                   
                 that is in contact 
                 membrane area 
                 integration in a 
               
               
                   
                 with the ink. 
                   
                 VLSI process 
               
               
                 Rotary 
                 The actuator causes 
                 Rotary levers 
                 Device 
                 IJ05, IJ08, IJ13, 
               
               
                   
                 the rotation of some 
                 may be used to 
                 complexity 
                 IJ28 
               
               
                   
                 element, such a grill 
                 increase travel 
                 May have 
               
               
                   
                 or impeller 
                 Small chip area 
                 friction at a 
               
               
                   
                   
                 requirements 
                 pivot point 
               
               
                 Bend 
                 The actuator bends 
                 A very small 
                 Requires the 
                 1970 Kyser et al U.S. Pat. No. 
               
               
                   
                 when energized. 
                 change in 
                 actuator to be 
                 3,946,398 
               
               
                   
                 This may be due to 
                 dimensions can 
                 made from at 
                 1973 Stemme U.S. Pat. No. 
               
               
                   
                 differential thermal 
                 be converted to 
                 least two 
                 3,747,120 
               
               
                   
                 expansion, 
                 a large motion. 
                 distinct layers, 
                 IJ03, IJ09, IJ10, 
               
               
                   
                 piezoelectric 
                   
                 or to have a 
                 IJ19, IJ23, IJ24, 
               
               
                   
                 expansion, 
                   
                 thermal 
                 IJ25, IJ29, IJ30, 
               
               
                   
                 magnetostriction, or 
                   
                 difference 
                 IJ31, IJ33, IJ34, 
               
               
                   
                 other form of 
                   
                 across the 
                 IJ35 
               
               
                   
                 relative dimensional 
                   
                 actuator 
               
               
                   
                 change. 
               
               
                 Swivel 
                 The actuator swivels 
                 Allows 
                 Inefficient 
                 IJ06 
               
               
                   
                 around a central 
                 operation where 
                 coupling to the 
               
               
                   
                 pivot. This motion is 
                 the net linear 
                 ink motion 
               
               
                   
                 suitable where there 
                 force on the 
               
               
                   
                 are opposite forces 
                 paddle is zero 
               
               
                   
                 applied to opposite 
                 Small chip area 
               
               
                   
                 sides of the paddle, 
                 requirements 
               
               
                   
                 e.g. Lorenz force. 
               
               
                 Straighten 
                 The actuator is 
                 Can be used 
                 Requires careful 
                 IJ26, IJ32 
               
               
                   
                 normally bent, and 
                 with shape 
                 balance of 
               
               
                   
                 straightens when 
                 memory alloys 
                 stresses to 
               
               
                   
                 energized. 
                 where the 
                 ensure that the 
               
               
                   
                   
                 austenic phase 
                 quiescent bend 
               
               
                   
                   
                 is planar 
                 is accurate 
               
               
                 Double 
                 The actuator bends 
                 One actuator 
                 Difficult to 
                 IJ36, IJ37, IJ38 
               
               
                 bend 
                 in one direction 
                 can be used to 
                 make the drops 
               
               
                   
                 when one element is 
                 power two 
                 ejected by both 
               
               
                   
                 energized, and 
                 nozzles. 
                 bend directions 
               
               
                   
                 bends the other way 
                 Reduced chip 
                 identical. 
               
               
                   
                 when another 
                 size. 
                 A small 
               
               
                   
                 element is 
                 Not sensitive to 
                 efficiency loss 
               
               
                   
                 energized. 
                 ambient 
                 compared to 
               
               
                   
                   
                 temperature 
                 equivalent 
               
               
                   
                   
                   
                 single bend 
               
               
                   
                   
                   
                 actuators. 
               
               
                 Shear 
                 Energizing the 
                 Can increase the 
                 Not readily 
                 1985 Fishbeck U.S. Pat. No. 
               
               
                   
                 actuator causes a 
                 effective travel 
                 applicable to 
                 4,584,590 
               
               
                   
                 shear motion in the 
                 of piezoelectric 
                 other actuator 
               
               
                   
                 actuator material. 
                 actuators 
                 mechanisms 
               
               
                 Radial 
                 The actuator 
                 Relatively easy 
                 High force 
                 1970 Zoltan U.S. Pat. No. 
               
               
                 con- 
                 squeezes an ink 
                 to fabricate 
                 required 
                 3,683,212 
               
               
                 striction 
                 reservoir, forcing 
                 single nozzles 
                 Inefficient 
               
               
                   
                 ink from a 
                 from glass 
                 Difficult to 
               
               
                   
                 constricted nozzle. 
                 tubing as 
                 integrate with 
               
               
                   
                   
                 macroscopic 
                 VLSI processes 
               
               
                   
                   
                 stractures 
               
               
                 Coil/ 
                 A coiled actuator 
                 Easy to 
                 Difficult to 
                 IJ17, IJ21, IJ34, 
               
               
                 uncoil 
                 uncoils or coils 
                 fabricate as a 
                 fabricate for 
                 IJ35 
               
               
                   
                 more tightly. The 
                 planar VLSI 
                 non-planar 
               
               
                   
                 motion of the free 
                 process 
                 devices 
               
               
                   
                 end of the actuator 
                 Small area 
                 Poor out-of- 
               
               
                   
                 ejects the ink. 
                 required, 
                 plane stiffness 
               
               
                   
                   
                 therefore low 
               
               
                   
                   
                 cost 
               
               
                 Bow 
                 The actuator bows 
                 Can increase the 
                 Maximum 
                 IJ16, IJ18, IJ27 
               
               
                   
                 (or buckles) in the 
                 speed of travel 
                 travel is 
               
               
                   
                 middle when 
                 Mechanically 
                 constrained 
               
               
                   
                 energized. 
                 rigid 
                 High force 
               
               
                   
                   
                   
                 required 
               
               
                 Push-Pull 
                 Two actuators 
                 The structure is 
                 Not readily 
                 IJ18 
               
               
                   
                 control a shutter. 
                 pinned at both 
                 suitable for ink 
               
               
                   
                 One actuator pulls 
                 ends, so has a 
                 jets which 
               
               
                   
                 the shutter, and the 
                 high out-of- 
                 directly push 
               
               
                   
                 other pushes it. 
                 plane rigidity 
                 the ink 
               
               
                 Curl 
                 A set of actuators 
                 Good fluid flow 
                 Design 
                 IJ20, IJ42 
               
               
                 inwards 
                 curl inwards to 
                 to the region 
                 complexity 
               
               
                   
                 reduce the volume 
                 behind the 
               
               
                   
                 of ink that they 
                 actuator 
               
               
                   
                 enclose. 
                 increases 
               
               
                   
                   
                 efficiency 
               
               
                 Curl 
                 A set of actuators 
                 Relatively 
                 Relatively large 
                 IJ43 
               
               
                 outwards 
                 curl outwards, 
                 simple 
                 chip area 
               
               
                   
                 pressurizing ink in a 
                 construction 
               
               
                   
                 chamber 
               
               
                   
                 surrounding the 
               
               
                   
                 actuators, and 
               
               
                   
                 expelling ink from a 
               
               
                   
                 nozzle in the 
               
               
                   
                 chamber. 
               
               
                 Iris 
                 Multiple vanes 
                 High efficiency 
                 High fabrication 
                 IJ22 
               
               
                   
                 enclose a volume of 
                 Small chip area 
                 complexity 
               
               
                   
                 ink. These 
                   
                 Not suitable for 
               
               
                   
                 simultaneously 
                   
                 pigmented inks 
               
               
                   
                 rotate, reducing the 
               
               
                   
                 volume between the 
               
               
                   
                 vanes. 
               
               
                 Acoustic 
                 The actuator 
                 The actuator 
                 Large area 
                 1993 Hadimioglu et al, 
               
               
                 vibration 
                 vibrates at a high 
                 can be 
                 required for 
                 EUP 550,192 
               
               
                   
                 frequency 
                 physically 
                 efficient 
                 1993 Elrod et al, EUP 
               
               
                   
                   
                 distant from the 
                 operation at 
                 572,220 
               
               
                   
                   
                 ink 
                 useful 
               
               
                   
                   
                   
                 frequencies 
               
               
                   
                   
                   
                 Acoustic 
               
               
                   
                   
                   
                 coupling and 
               
               
                   
                   
                   
                 crosstalk 
               
               
                   
                   
                   
                 Complex drive 
               
               
                   
                   
                   
                 circuitry 
               
               
                   
                   
                   
                 Poor control of 
               
               
                   
                   
                   
                 drop volume 
               
               
                   
                   
                   
                 and position 
               
               
                 None 
                 In various ink jet 
                 No moving 
                 Various other 
                 Silverbrook, EP 0771 658 A2 
               
               
                   
                 designs the actuator 
                 parts 
                 tradeoffs are 
                 and related patent 
               
               
                   
                 does not move. 
                   
                 required to 
                 applications 
               
               
                   
                   
                   
                 eliminate 
                 Tone-jet 
               
               
                   
                   
                   
                 moving parts 
               
            
           
           
               
            
               
                 Nozzle refill method 
               
            
           
           
               
               
               
               
               
            
               
                 Surface 
                 This is the normal 
                 Fabrication 
                 Low speed 
                 Thermal ink jet 
               
               
                 tension 
                 way that inkjets are 
                 simplicity 
                 Surface tension 
                 Piezoelectric ink jet 
               
               
                   
                 refilled. After the 
                 Operational 
                 force relatively 
                 IJ01-IJ07, IJ10- 
               
               
                   
                 actuator is energized, 
                 simplicity 
                 small 
                 IJ14, IJ16, IJ20, 
               
               
                   
                 it typically returns 
                   
                 compared to 
                 IJ22-IJ45 
               
               
                   
                 rapidly to its normal 
                   
                 actuator force 
               
               
                   
                 position. This rapid 
                   
                 Long refill 
               
               
                   
                 return sucks in air 
                   
                 time usually 
               
               
                   
                 through the nozzle 
                   
                 dominates the 
               
               
                   
                 opening. The ink 
                   
                 total repetition 
               
               
                   
                 surface tension at the 
                   
                 rate 
               
               
                   
                 nozzle then exerts a 
               
               
                   
                 small force restoring 
               
               
                   
                 the meniscus to a 
               
               
                   
                 minimum area. This 
               
               
                   
                 force refills the 
               
               
                   
                 nozzle. 
               
               
                 Shuttered 
                 Ink to the nozzle 
                 High speed 
                 Requires 
                 IJ08, IJ13, IJ15, 
               
               
                 oscillating 
                 chamber is provided 
                 Low actuator 
                 common ink 
                 IJ17, IJ18, IJ19, 
               
               
                 ink 
                 at a pressure that 
                 energy, as the 
                 pressure 
                 IJ21 
               
               
                 pressure 
                 oscillates at twice the 
                 actuator need 
                 oscillator 
               
               
                   
                 drop ejection 
                 only open or 
                 May not be 
               
               
                   
                 frequency. When a 
                 close the 
                 suitable for 
               
               
                   
                 drop is to be ejected, 
                 shutter, instead 
                 pigmented inks 
               
               
                   
                 the shutter is opened 
                 of ejecting the 
               
               
                   
                 for 3 half cycles: 
                 ink drop 
               
               
                   
                 drop ejection, 
               
               
                   
                 actuator return, and 
               
               
                   
                 refill. The shutter is 
               
               
                   
                 then closed to prevent 
               
               
                   
                 the nozzle chamber 
               
               
                   
                 emptying during the 
               
               
                 Refill 
                 After the main 
                 High speed, as 
                 Requires two 
                 IJ09 
               
               
                 actuator 
                 actuator has ejected a 
                 the nozzle is 
                 independent 
               
               
                   
                 drop a second (refill) 
                 actively 
                 actuators per 
               
               
                   
                 actuator is energized. 
                 refilled 
                 nozzle 
               
               
                   
                 The refill actuator 
               
               
                   
                 pushes ink into the 
               
               
                   
                 nozzle chamber. The 
               
               
                   
                 refill actuator returns 
               
               
                   
                 slowly, to prevent its 
               
               
                   
                 return from emptying 
               
               
                   
                 the chamber again. 
               
               
                 Positive 
                 The ink is held a 
                 High refill rate, 
                 Surface spill 
                 Silverbrook, EP 0771 658 A2 
               
               
                 ink 
                 slight positive 
                 therefore a 
                 must be 
                 and related patent 
               
               
                 pressure 
                 pressure. After the 
                 high drop 
                 prevented 
                 applications 
               
               
                   
                 ink drop is ejected, 
                 repetition rate 
                 Highly 
                 Alternative for: 
               
               
                   
                 the nozzle chamber 
                 is possible 
                 hydrophobic 
                 IJ01-IJ07, IJ10-IJ14, 
               
               
                   
                 fllls quickly as 
                   
                 print head 
                 IJ16, IJ20, IJ22-IJ45 
               
               
                   
                 surface tension and 
                   
                 surfaces are 
               
               
                   
                 ink pressure both 
                   
                 required 
               
               
                   
                 operate to refill the 
               
               
                   
                 nozzle. 
               
            
           
           
               
            
               
                 Method of restricting back-flow through inlet 
               
            
           
           
               
               
               
               
               
            
               
                 Long inlet 
                 The ink inlet 
                 Design 
                 Restricts refill 
                 Thermal ink jet 
               
               
                 channel 
                 channel to the 
                 simplicity 
                 rate 
                 Piezoelectric ink jet 
               
               
                   
                 nozzle chamber is 
                 Operational 
                 May result in a 
                 IJ42, IJ43 
               
               
                   
                 made long and 
                 simplicity 
                 relatively large 
               
               
                   
                 relatively narrow, 
                 Reduces 
                 chip area 
               
               
                   
                 relying on viscous 
                 crosstalk 
                 Only partially 
               
               
                   
                 drag to reduce inlet 
                   
                 effective 
               
               
                   
                 back-flow. 
               
               
                 Positive 
                 The ink is under a 
                 Drop selection 
                 Requires a 
                 Silverbrook, EP 0771 658 A2 
               
               
                 ink 
                 positive pressure, so 
                 and separation 
                 method (such 
                 and related patent 
               
               
                 pressure 
                 that in the quiescent 
                 forces can be 
                 as a nozzle rim 
                 applications 
               
               
                   
                 state some of the ink 
                 reduced 
                 or effective 
                 Possible operation of the 
               
               
                   
                 drop already 
                 Fast refill time 
                 hydrophobizing, 
                 following: 
               
               
                   
                 protrudes from the 
                   
                 or both) to 
                 IJ01-IJ07, IJ09-IJ12, 
               
               
                   
                 nozzle. 
                   
                 prevent 
                 IJ14, IJ16, IJ20, 
               
               
                   
                 This reduces the 
                   
                 flooding of the 
                 IJ22, IJ23-IJ34, 
               
               
                   
                 pressure in the 
                   
                 ejection 
                 IJ36-IJ41, IJ44 
               
               
                   
                 nozzle chamber 
                   
                 surface of the 
               
               
                   
                 which is required to 
                   
                 print head. 
               
               
                   
                 eject a certain 
               
               
                   
                 volume of ink. The 
               
               
                   
                 reduction in 
               
               
                   
                 chamber pressure 
               
               
                   
                 results in a reduction 
               
               
                   
                 in ink pushed out 
               
               
                   
                 through the inlet. 
               
               
                 Baffle 
                 One or more baffles 
                 The refill rate is 
                 Design 
                 HP Thermal Ink Jet 
               
               
                   
                 are placed in the 
                 not as restricted 
                 complexity 
                 Tektronix piezoelectric ink 
               
               
                   
                 inlet ink flow. When 
                 as the long inlet 
                 May increase 
                 jet 
               
               
                   
                 the actuator is 
                 method. 
                 fabrication 
               
               
                   
                 energized, the rapid 
                 Reduces 
                 complexity 
               
               
                   
                 ink movement 
                 crosstalk 
                 (e.g. Tektronix 
               
               
                   
                 creates eddies which 
                   
                 hot melt 
               
               
                   
                 restrict the flow 
                   
                 Piezoelectric 
               
               
                   
                 through the inlet. 
                   
                 print heads). 
               
               
                   
                 The slower refill 
               
               
                   
                 process is 
               
               
                   
                 unrestricted, and 
               
               
                   
                 does not result in 
               
               
                   
                 eddies. 
               
               
                 Flexible 
                 In this method 
                 Significantly 
                 Not applicable 
                 Canon 
               
               
                 flap 
                 recently disclosed 
                 reduces back- 
                 to most ink jet 
               
               
                 restricts 
                 by Canon, the 
                 flow for edge- 
                 configurations 
               
               
                 inlet 
                 expanding actuator 
                 shooter thermal 
                 Increased 
               
               
                   
                 (bubble) pushes on a 
                 ink jet devices 
                 fabrication 
               
               
                   
                 flexible flap that 
                   
                 complexity 
               
               
                   
                 restricts the inlet. 
                   
                 Inelastic 
               
               
                   
                   
                   
                 deformation of 
               
               
                   
                   
                   
                 polymer flap 
               
               
                   
                   
                   
                 results in creep 
               
               
                   
                   
                   
                 over extended 
               
               
                   
                   
                   
                 use 
               
               
                 Inlet filter 
                 A filter is located 
                 Additional 
                 Restricts refill 
                 IJ04, IJ12, IJ24, 
               
               
                   
                 between the ink inlet 
                 advantage of 
                 rate 
                 IJ27, IJ29, IJ30 
               
               
                   
                 and the nozzle 
                 ink filtration 
                 May result in 
               
               
                   
                 chamber. The filter 
                 Ink filter may 
                 complex 
               
               
                   
                 has a multitude of 
                 be fabricated 
                 construction 
               
               
                   
                 small holes or slots, 
                 with no 
               
               
                   
                 restricting ink flow. 
                 additional 
               
               
                   
                 The filter also 
                 process steps 
               
               
                   
                 removes particles 
               
               
                   
                 which may block the 
               
               
                   
                 nozzle. 
               
               
                 Small inlet 
                 The ink inlet 
                 Design 
                 Restricts refill 
                 IJ02, IJ37, IJ44 
               
               
                 compared 
                 channel to the 
                 simplicity 
                 rate 
               
               
                 to nozzle 
                 nozzle chamber has 
                   
                 May result in a 
               
               
                   
                 a substantially 
                   
                 relatively large 
               
               
                   
                 smaller cross section 
                   
                 chip area 
               
               
                   
                 than that of the 
                   
                 Only partially 
               
               
                   
                 nozzle, resulting in 
                   
                 effective 
               
               
                   
                 easier ink egress out 
               
               
                   
                 of the nozzle than 
               
               
                   
                 out of the inlet. 
               
               
                 Inlet 
                 A secondary 
                 Increases speed 
                 Requires 
                 IJ09 
               
               
                 shutter 
                 actuator controls the 
                 of the ink jet 
                 separate refill 
               
               
                   
                 position of a shutter, 
                 print head 
                 actuator and 
               
               
                   
                 closing off the ink 
                 operation 
                 drive circuit 
               
               
                   
                 inlet when the main 
               
               
                   
                 actuator is 
               
               
                   
                 energized. 
               
               
                 The inlet 
                 The method avoids 
                 Back-flow 
                 Requires 
                 IJ01, IJ03, IJ05, 
               
               
                 is located 
                 the problem of inlet 
                 problem is 
                 careful design 
                 IJ06, IJ07. IJ10, 
               
               
                 behind the 
                 back-flow by 
                 eliminated 
                 to minimize 
                 IJ11, IJ14, IJ16, 
               
               
                 ink- 
                 arranging the ink- 
                   
                 the negative 
                 IJ22, IJ23, IJ25, 
               
               
                 pushing 
                 pushing surface of 
                   
                 pressure 
                 IJ28, IJ31, IJ32, 
               
               
                 surtace 
                 the actuator between 
                   
                 behind the 
                 IJ33, IJ34, IJ35, 
               
               
                   
                 the inlet and the 
                   
                 paddle 
                 IJ36, IJ39, IJ40, 
               
               
                   
                 nozzle. 
                   
                   
                 IJ41 
               
               
                 Part of the 
                 The actuator and a 
                 Significant 
                 Small increase 
                 IJ07, IJ20, IJ26, 
               
               
                 actuator 
                 wall of the ink 
                 reductions in 
                 in fabrication 
                 IJ38 
               
               
                 moves to 
                 chamber are 
                 back-flow can 
                 complexity 
               
               
                 shut off 
                 arranged so that the 
                 be achieved 
               
               
                 the inlet 
                 motion of the 
                 Compact 
               
               
                   
                 actuator closes off 
                 designs possible 
               
               
                   
                 the inlet. 
               
               
                 Nozzle 
                 In some 
                 Ink back-flow 
                 None related to 
                 Silverbrook, EP 0771 658 A2 
               
               
                 actuator 
                 configurations of 
                 problem is 
                 ink back-flow 
                 and related patent 
               
               
                 does not 
                 ink jet, there is no 
                 eliminated 
                 on actuation 
                 applications 
               
               
                 result in 
                 expansion or 
                   
                   
                 Valve-jet 
               
               
                 ink back- 
                 movement of an 
                   
                   
                 Tone-jet 
               
               
                 flow 
                 actuator which may 
               
               
                   
                 cause ink back-flow 
               
               
                   
                 through the inlet. 
               
            
           
           
               
            
               
                 Nozzle clearing method 
               
            
           
           
               
               
               
               
               
            
               
                 Normal 
                 All of the nozzles 
                 No added 
                 May not be 
                 Most ink jet systems 
               
               
                 nozzle 
                 are fired 
                 complexity on 
                 sufficient to 
                 IJ01, IJ02, IJ03, 
               
               
                 firing 
                 periodically, before 
                 the print head 
                 displace dried 
                 IJ04, IJ05, IJ06, 
               
               
                   
                 the ink has a chance 
                   
                 ink 
                 IJ07, IJ09, IJ10, 
               
               
                   
                 to dry. When not in 
                   
                   
                 IJ11, IJ12, IJ14, 
               
               
                   
                 use the nozzles are 
                   
                   
                 IJ16, IJ20, IJ22, 
               
               
                   
                 sealed (capped) 
                   
                   
                 IJ23, IJ24, IJ25, 
               
               
                   
                 against air. 
                   
                   
                 IJ26, IJ27, IJ28, 
               
               
                   
                 The nozzle firing is 
                   
                   
                 IJ29, IJ30, IJ31, 
               
               
                   
                 usually performed 
                   
                   
                 IJ32, IJ33, IJ34, 
               
               
                   
                 during a special 
                   
                   
                 IJ36, IJ37, IJ38, 
               
               
                   
                 clearing cycle, after 
                   
                   
                 IJ39, IJ40, IJ41, 
               
               
                   
                 first moving the 
                   
                   
                 IJ42, IJ43, IJ44, 
               
               
                   
                 print head to a 
                   
                   
                 IJ45 
               
               
                   
                 cleaning station. 
               
               
                 Extra 
                 In systems which 
                 Can be highly 
                 Requires 
                 Silverbrook, EP 0771 658 A2 
               
               
                 power to 
                 heat the ink, but do 
                 effective if the 
                 higher drive 
                 and related patent 
               
               
                 ink heater 
                 not boil it under 
                 heater is 
                 voltage for 
                 applications 
               
               
                   
                 normal situations, 
                 adjacent to the 
                 clearing 
               
               
                   
                 nozzle clearing can 
                 nozzle 
                 May require 
               
               
                   
                 be achieved by over- 
                   
                 larger drive 
               
               
                   
                 powering the heater 
                   
                 transistors 
               
               
                   
                 and boiling ink at 
               
               
                   
                 the nozzle. 
               
               
                 Rapid 
                 The actuator is fired 
                 Does not 
                 Effectiveness 
                 May be used with: 
               
               
                 success- 
                 in rapid succession. 
                 require extra 
                 depends 
                 IJ01, IJ02, IJ03, 
               
               
                 ion of 
                 In some 
                 drive circuits on 
                 substantially 
                 IJ04, IJ05, IJ06, 
               
               
                 actuator 
                 configurations, this 
                 the print head 
                 upon the 
                 IJ07, IJ09, IJ10, 
               
               
                 pulses 
                 may cause heat 
                 Can be readily 
                 configuration 
                 IJ11, IJ14, IJ16, 
               
               
                   
                 build-up at the 
                 controlled and 
                 of the inkjet 
                 IJ20, IJ22, IJ23, 
               
               
                   
                 nozzle which boils 
                 initiated by 
                 nozzle 
                 IJ24, IJ25, IJ27, 
               
               
                   
                 the ink, clearing the 
                 digital logic 
                   
                 IJ28, IJ29, IJ30, 
               
               
                   
                 nozzle. In other 
                   
                   
                 IJ31, IJ32, IJ33, 
               
               
                   
                 situations, it may 
                   
                   
                 IJ34, IJ36, IJ37, 
               
               
                   
                 cause sufficient 
                   
                   
                 IJ38, IJ39, IJ40, 
               
               
                   
                 vibrations to 
                   
                   
                 IJ41, IJ42, IJ43, 
               
               
                   
                 dislodge clogged 
                   
                   
                 IJ44, IJ45 
               
               
                   
                 nozzles. 
               
               
                 Extra 
                 Where an actuator is 
                 A simple 
                 Not suitable 
                 May be used with: 
               
               
                 power to 
                 not normally driven 
                 solution where 
                 where there is 
                 IJ03, IJ09, IJ16, 
               
               
                 ink 
                 to the limit of its 
                 applicable 
                 a hard limit to 
                 IJ20, IJ23, IJ24, 
               
               
                 pushing 
                 motion, nozzle 
                   
                 actuator 
                 IJ25, IJ27, IJ29, 
               
               
                 actuator 
                 clearing may be 
                   
                 movement 
                 IJ30, IJ31, IJ32, 
               
               
                   
                 assisted by 
                   
                   
                 IJ39, IJ40, IJ41, 
               
               
                   
                 providing an 
                   
                   
                 IJ42, IJ43, IJ44, 
               
               
                   
                 enhanced drive 
                   
                   
                 IJ45 
               
               
                   
                 signal to the 
               
               
                   
                 actuator. 
               
               
                 Acoustic 
                 An ultrasonic wave 
                 A high nozzle 
                 High 
                 IJ08, IJ13, IJ15, 
               
               
                 resonance 
                 is applied to the ink 
                 clearing 
                 implementation 
                 IJ17, IJ18, IJ19, 
               
               
                   
                 chamber. This wave 
                 capability can 
                 cost if 
                 IJ21 
               
               
                   
                 is of an appropriate 
                 he achieved 
                 system does 
               
               
                   
                 amptitude and 
                 May be 
                 not already 
               
               
                   
                 frequency to cause 
                 implemented at 
                 include an 
               
               
                   
                 sufficient force at 
                 very low cost in 
                 acoustic 
               
               
                   
                 the nozzle to clear 
                 systems which 
                 actuator 
               
               
                   
                 blockages. This is 
                 already include 
               
               
                   
                 easiest to achieve if 
                 acoustic 
               
               
                   
                 the ultrasonic wave 
                 actuator 
               
               
                   
                 is at a resonant 
               
               
                   
                 frequency of the ink 
               
               
                   
                 cavity. 
               
               
                 Nozzle 
                 A microfabricated 
                 Can clear 
                 Accurate 
                 Silverbrook, EP 0771 658 A2 
               
               
                 clearing 
                 plate is pushed 
                 severely 
                 mechanical 
                 and related patent 
               
               
                 plate 
                 against the nozzles. 
                 clogged nozzles 
                 alignment is 
                 applications 
               
               
                   
                 The plate has a post 
                   
                 required 
               
               
                   
                 for every nozzle. A 
                   
                 Moving parts 
               
               
                   
                 post moves through 
                   
                 are required 
               
               
                   
                 each nozzle, 
                   
                 There is risk of 
               
               
                   
                 displacing dried ink. 
                   
                 damage to the 
               
               
                   
                   
                   
                 nozzles 
               
               
                   
                   
                   
                 Accurate 
               
               
                   
                   
                   
                 fabrication is 
               
               
                   
                   
                   
                 required 
               
               
                 Ink 
                 The pressure of the 
                 May be 
                 Requires 
                 May be used with all IJ 
               
               
                 pressure 
                 ink is temporarily 
                 effective where 
                 pressure pump 
                 series ink jets 
               
               
                 pulse 
                 increased so that ink 
                 other methods 
                 or other 
               
               
                   
                 streams from all of 
                 cannot be used 
                 pressure 
               
               
                   
                 the nozzles. This 
                   
                 actuator 
               
               
                   
                 may be used in 
                   
                 Expensive 
               
               
                   
                 conjunction with 
                   
                 Wasteful of 
               
               
                   
                 actuator energizing. 
                   
                 ink 
               
               
                 Print head 
                 A flexible ‘blade’ is 
                 Effective for 
                 Difficult to use 
                 Many ink jet systems 
               
               
                 wiper 
                 wiped across the 
                 planar print 
                 if print head 
               
               
                   
                 print head surface. 
                 head surfaces 
                 surface is non- 
               
               
                   
                 The blade is usually 
                 Low cost 
                 planar or very 
               
               
                   
                 fabricated from a 
                   
                 fragile 
               
               
                   
                 flexible polymer, 
                   
                 Requires 
               
               
                   
                 e.g. rubber or 
                   
                 mechanical 
               
               
                   
                 synthetic elastomer. 
                   
                 parts 
               
               
                   
                   
                   
                 Blade can wear 
               
               
                   
                   
                   
                 out in high 
               
               
                   
                   
                   
                 volume print 
               
               
                   
                   
                   
                 systems 
               
               
                 Separate 
                 A separate heater is 
                 Can be effective 
                 Fabrication 
                 Can be used with many IJ 
               
               
                 ink boiling 
                 provided at the 
                 where other 
                 complexity 
                 series ink jets 
               
               
                 heater 
                 nozzle although the 
                 nozzle clearing 
               
               
                   
                 normal drop e- 
                 methods cannot 
               
               
                   
                 ection mechanism 
                 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 be 
                 jet 
               
               
                   
                 cleared 
                 configuration 
               
               
                   
                 simultaneously, and 
               
               
                   
                 no imaging is 
               
               
                   
                 required. 
               
            
           
           
               
            
               
                 Nozzle plate construction 
               
            
           
           
               
               
               
               
               
            
               
                 Electro- 
                 A nozzle plate is 
                 Fabrication 
                 High 
                 Hewlett Packard Thermal 
               
               
                 formed 
                 separately fabricated 
                 simplicity 
                 temperatures 
                 Ink jet 
               
               
                 nickel 
                 from electroformed 
                   
                 and pressures 
               
               
                   
                 nickel, and bonded 
                   
                 are required to 
               
               
                   
                 to the print head 
                   
                 bond nozzle 
               
               
                   
                 chip. 
                   
                 plate 
               
               
                   
                   
                   
                 Minimum 
               
               
                   
                   
                   
                 thickness 
               
               
                   
                   
                   
                 constraints 
               
               
                   
                   
                   
                 Differential 
               
               
                   
                   
                   
                 thermal 
               
               
                   
                   
                   
                 expansion 
               
               
                 Laser 
                 Individual nozzle 
                 No masks 
                 Each hole must 
                 Canon Bubblejet 
               
               
                 ablated or 
                 holes are ablated by 
                 required 
                 be individually 
                 1988 Sercel et al., SPIE, 
               
               
                 drilled 
                 an intense UV laser 
                 Can be quite 
                 formed 
                 Vol. 998 Excimer Beam 
               
               
                 polymer 
                 in a nozzle plate, 
                 fast 
                 Special 
                 Applications, pp. 76-83 
               
               
                   
                 which is typically a 
                 Some control 
                 equipment 
                 1993 Watanabe et al., 
               
               
                   
                 polymer such as 
                 over nozzle 
                 required 
                 U.S. Pat. No. 5,208,604 
               
               
                   
                 polyimide or 
                 profile is 
                 Slow where 
               
               
                   
                 polysulphone 
                 possible 
                 there are many 
               
               
                   
                   
                 Equipment 
                 thousands of 
               
               
                   
                   
                 required is 
                 nozzles per 
               
               
                   
                   
                 relatively low 
                 print head 
               
               
                   
                   
                 cost 
                 May produce 
               
               
                   
                   
                   
                 thin burrs at 
               
               
                   
                   
                   
                 exit holes 
               
               
                 Silicon 
                 A separate nozzle 
                 High accuracy 
                 Two part 
                 K. Bean, IEEE 
               
               
                 micro- 
                 plate is 
                 is attainable 
                 construction 
                 Transactions on Electron 
               
               
                 machined 
                 micromachined 
                   
                 High cost 
                 Devices, Vol. ED-25, No. 
               
               
                   
                 from single crystal 
                   
                 Requires 
                 10, 1978, pp 1185-1195 
               
               
                   
                 silicon, and bonded 
                   
                 precision 
                 Xerox 1990 Hawkins et al., 
               
               
                   
                 to the print head 
                   
                 alignment 
                 U.S. Pat. No. 4,899,191 
               
               
                   
                 wafer. 
                   
                 Nozzles may 
               
               
                   
                   
                   
                 be clogged by 
               
               
                   
                   
                   
                 adhesive 
               
               
                 Glass 
                 Fine glass 
                 No expensive 
                 Very small 
                 1970 Zoltan U.S. Pat. No. 
               
               
                 capillaries 
                 capillaries are drawn 
                 equipment 
                 nozzle sizes 
                 3,683,212 
               
               
                   
                 from glass tubing. 
                 required 
                 are difficult to 
               
               
                   
                 This method has 
                 Simple to make 
                 form 
               
               
                   
                 been used for 
                 single nozzles 
                 Not suited for 
               
               
                   
                 making individual 
                   
                 mass 
               
               
                   
                 nozzles, but is 
                   
                 production 
               
               
                   
                 difficult to use for 
               
               
                   
                 bulk manufacturing 
               
               
                   
                 of print heads with 
               
               
                   
                 thousands of 
               
               
                   
                 nozzles. 
               
               
                 Monolithic, 
                 The nozzle plate is 
                 High accuracy 
                 Requires 
                 Silverbrook, EP 0771 658 A2 
               
               
                 surface 
                 deposited as a layer 
                 (&lt;1 μm) 
                 sacrificial layer 
                 and related patent 
               
               
                 micro- 
                 using standard VLSI 
                 Monolitnic 
                 under the 
                 applications 
               
               
                 machined 
                 deposition 
                 Low cost 
                 nozzle plate to 
                 IJ01, IJ02, IJ04, 
               
               
                 using VLSI 
                 techniques. Nozzles 
                 Existing 
                 form the 
                 IJ11, IJ12, IJ17, 
               
               
                 litho- 
                 are etched in the 
                 processes can 
                 nozzle 
                 IJ18, IJ20, IJ22, 
               
               
                 graphic 
                 nozzle plate using 
                 be used 
                 chamber 
                 IJ24, IJ27, IJ28, 
               
               
                 processes 
                 VLSI lithography 
                   
                 Surface may 
                 IJ29, IJ30, IJ31, 
               
               
                   
                 and etching. 
                   
                 be fragile to 
                 IJ32, IJ33, IJ34, 
               
               
                   
                   
                   
                 the touch 
                 IJ36, IJ37, IJ38, 
               
               
                   
                   
                   
                   
                 IJ39, IJ40, IJ41, 
               
               
                   
                   
                   
                   
                 IJ42, IJ43, IJ44 
               
               
                 Monolithic, 
                 The nozzle plate is a 
                 High accuracy 
                 Requires long 
                 IJ03, IJ05, IJ06, 
               
               
                 etched 
                 buried etch stop in 
                 (&lt;1 μm) 
                 etch times 
                 IJ07, IJ08, IJ09, 
               
               
                 through 
                 the wafer. Nozzle 
                 Monolithic 
                 Requires a 
                 IJ10, IJ13, IJ14, 
               
               
                 substrate 
                 chambers are etched 
                 Low cost 
                 support wafer 
                 IJ15, IJ16, IJ19, 
               
               
                   
                 in the front of the 
                 No differential 
                   
                 IJ21, IJ23, IJ25, 
               
               
                   
                 wafer, and the wafer 
                 expansion 
                   
                 IJ26 
               
               
                   
                 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 Sekiya et al 
               
               
                 plate 
                 have been tried to 
                 become clogged 
                 control drop 
                 U.S. Pat. No. 5,412,413 
               
               
                   
                 eliminate the 
                   
                 position 
                 1993 Hadimioglu et al EUP 
               
               
                   
                 nozzles entirely, to 
                   
                 accurately 
                 550,192 
               
               
                   
                 prevent nozzle 
                   
                 Crosstalk 
                 1993 Elrod et al EUP 
               
               
                   
                 clogging. These 
                   
                 problems 
                 572,220 
               
               
                   
                 include thermal 
               
               
                   
                 bubble mechanisms 
               
               
                   
                 and acoustic lens 
               
               
                   
                 mechanisms 
               
               
                 Trough 
                 Each drop ejector 
                 Reduced 
                 Drop flring 
                 IJ35 
               
               
                   
                 has a trough through 
                 manufacturing 
                 direction is 
               
               
                   
                 which a paddle 
                 complexity 
                 sensitive to 
               
               
                   
                 moves. There is no 
                 Monolithic 
                 wicking. 
               
               
                   
                 nozzle plate. 
               
               
                 Nozzle slit 
                 The elimination of 
                 No nozzles to 
                 Difficult to 
                 1989 Saito et al 
               
               
                 instead of 
                 nozzle holes and 
                 become clogged 
                 control drop 
                 U.S. Pat. No. 4,799,068 
               
               
                 individual 
                 replacement by a slit 
                   
                 position 
               
               
                 nozzles 
                 encompassing many 
                   
                 accurately 
               
               
                   
                 actuator positions 
                   
                 Crosstalk 
               
               
                   
                 reduces nozzle 
                   
                 problems 
               
               
                   
                 clogging, but 
               
               
                   
                 increases crosstalk 
               
               
                   
                 due to ink surface 
               
               
                   
                 waves 
               
            
           
           
               
            
               
                 Drop ejection direction 
               
            
           
           
               
               
               
               
               
            
               
                 Edge 
                 Ink flow is along the 
                 Simple 
                 Nozzles 
                 Canon Bubblejet 1979 
               
               
                 (‘edge 
                 surface of the chip, 
                 construction 
                 limited to edge 
                 Endo et al GB patent 
               
               
                 shooter’) 
                 and ink drops are 
                 No silicon 
                 High 
                 2,007,162 
               
               
                   
                 ejected from the 
                 etching required 
                 resolution is 
                 Xerox heater-in-pit 1990 
               
               
                   
                 chip edge. 
                 Good heat 
                 difficult 
                 Hawkins et al U.S. Pat. No. 
               
               
                   
                   
                 sinking via 
                 Fast color 
                 4,899,181 
               
               
                   
                   
                 substrate 
                 printing 
                 Tone-jet 
               
               
                   
                   
                 Mechanically 
                 requires one 
               
               
                   
                   
                 strong 
                 print head per 
               
               
                   
                   
                 Ease of chip 
                 color 
               
               
                   
                   
                 handing 
               
               
                 Surface 
                 Ink flow is along the 
                 No bulk silicon 
                 Maximum ink 
                 Hewlett-Packard TIJ 1982 
               
               
                 (‘roof 
                 surface of the chip, 
                 etching required 
                 flow is 
                 Vaught et al U.S. Pat. No. 
               
               
                 shooter’) 
                 and ink drops are 
                 Silicon can 
                 severely 
                 4,490,728 
               
               
                   
                 ejected from. the 
                 make an 
                 restricted 
                 IJ02, IJ11, IJ12, 
               
               
                   
                 chip surface, normal 
                 effective heat 
                   
                 IJ20, IJ22 
               
               
                   
                 to the plane of the 
                 sink 
               
               
                   
                 chip. 
                 Mechanical 
               
               
                   
                   
                 strength 
               
               
                 Through 
                 Ink flow is through. 
                 High ink flow 
                 Requires bulk 
                 Silverbrook, EP 0771 658 A2 
               
               
                 chip, 
                 the chip, and ink 
                 Suitable for 
                 silicon etching 
                 and related patent 
               
               
                 forward 
                 drops are ejected 
                 pagewidth print 
                   
                 applications 
               
               
                 (‘up 
                 from the front 
                 heads 
                   
                 IJ04, IJ17, IJ18, 
               
               
                 shooter’) 
                 surface of the chip. 
                 High nozzle 
                   
                 IJ24, IJ27-IJ45 
               
               
                   
                   
                 packing density 
               
               
                   
                   
                 therfore low 
               
               
                   
                   
                 manufacturing 
               
               
                 Through 
                 Ink flow is through 
                 High ink flow 
                 Requires wafer 
                 IJ01, IJ03, IJ05, 
               
               
                 chip, 
                 the chip, and ink 
                 Suitable for 
                 thinning 
                 IJ06, IJ07, IJ08, 
               
               
                 reverse 
                 drops are ejected 
                 pagewidth print 
                 Requires 
                 IJ09, IJ10, IJ13, 
               
               
                 (‘down 
                 from the rear surface 
                 heads 
                 special 
                 IJ14, IJ15, IJ16, 
               
               
                 shooter’) 
                 of the chip. 
                 High nozzle 
                 handling 
                 IJ19, IJ21, IJ23, 
               
               
                   
                   
                 packing density 
                 during 
                 IJ25, IJ26 
               
               
                   
                   
                 therefore low 
                 manufacture 
               
               
                   
                   
                 manufacturing 
               
               
                   
                   
                 cost 
               
               
                 Through 
                 Inkflow is through 
                 Suitable for 
                 Pagewidth 
                 Epson Stylus 
               
               
                 actuator 
                 the actuator, which 
                 piezoelectric 
                 print heads 
                 Tektronix hot melt 
               
               
                   
                 is not fabricated as 
                 print heads 
                 require several 
                 piezoelectric ink jets 
               
               
                   
                 part of the same 
                   
                 thousand 
               
               
                   
                 substrate as the 
                   
                 connections to 
               
               
                   
                 drive transistors. 
                   
                 drive circuits 
               
               
                   
                   
                   
                 Cannot be 
               
               
                   
                   
                   
                 manufactured 
               
               
                   
                   
                   
                 in standard 
               
               
                   
                   
                   
                 CMOS fabs 
               
               
                   
                   
                   
                 Complex 
               
               
                   
                   
                   
                 assembly 
               
               
                   
                   
                   
                 required 
               
            
           
           
               
            
               
                 Ink type 
               
            
           
           
               
               
               
               
               
            
               
                 Aqueous, 
                 Water based ink 
                 Environmentally 
                 Slow drying 
                 Most existing inkjets 
               
               
                 dye 
                 which typically 
                 friendly 
                 Corrosive 
                 All IJ series ink jets 
               
               
                   
                 contains: water, dye, 
                 No odor 
                 Bleeds on 
                 Silverbrook, EP 0771 658 A2 
               
               
                   
                 surfactant, 
                   
                 paper 
                 and related patent applications 
               
               
                   
                 humectant, and 
                   
                 May 
               
               
                   
                 biocide 
                   
                 strikethrough 
               
               
                   
                 Modern ink dyes 
                   
                 Cockles paper 
               
               
                   
                 have high water- 
               
               
                   
                 fastness, light 
               
               
                   
                 fastness 
               
               
                 Aqueous, 
                 Water based ink 
                 Environmentally 
                 Slow drying 
                 IJ02, IJ04, IJ21, 
               
               
                 pigment 
                 which typically 
                 friendly 
                 Corrosive 
                 IJ26, IJ27, IJ30 
               
               
                   
                 contains: water, 
                 No odor 
                 Pigment may 
                 Silverbrook, EP 0771 658 A2 
               
               
                   
                 pigment, surfactant, 
                 Reduced bleed 
                 clog nozzles 
                 and related patent 
               
               
                   
                 humectant, and 
                 Reduced 
                 Pigment may 
                 applications 
               
               
                   
                 biocide. 
                 wicking 
                 clog actuator 
                 Piezoelectric ink-jets 
               
               
                   
                 Pigments have an 
                 Reduced 
                 mechanisms 
                 Thermal ink jets (with 
               
               
                   
                 advantage in reduced 
                 strikethrough 
                 Cockles paper 
                 significant restrictions) 
               
               
                   
                 bleed, wicking and 
               
               
                   
                 strikethrough. 
               
               
                 Methyl 
                 MEK is a highly 
                 Very fast 
                 Odorous 
                 All IJ series ink jets 
               
               
                 Ethyl 
                 volatile solvent used 
                 drying 
                 Flammable 
               
               
                 Ketone 
                 for industrial printing 
                 Prints on 
               
               
                 (MEK) 
                 on difficult surfaces 
                 various 
               
               
                   
                 such as aluminum 
                 substrates such 
               
               
                   
                 cans. 
                 as metals and 
               
               
                   
                   
                 plastics 
               
               
                 Alcohol 
                 Alcohol based inks 
                 Fast drying 
                 Slight odor 
                 All IJ series ink jets 
               
               
                 (ethanol, 
                 can be used where 
                 Operates at 
                 Flammable 
               
               
                 2-butanol, 
                 the printer must 
                 sub-freezing 
               
               
                 and 
                 operate at 
                 temperatures 
               
               
                 others) 
                 temperatures below 
                 Reduced paper 
               
               
                   
                 the freezing point of 
                 cockle 
               
               
                   
                 water. An example of 
                 Low cost 
               
               
                   
                 this is in-camera 
               
               
                   
                 consumer 
               
               
                   
                 photographic 
               
               
                   
                 printing. 
               
               
                 Phase 
                 The ink is solid at 
                 No drying 
                 High viscosity 
                 Tektronix hot melt 
               
               
                 change 
                 room temperature, 
                 time-ink 
                 Printed ink 
                 piezoelectric ink jets 
               
               
                 (hot melt) 
                 and is melted in the 
                 instantly 
                 typically has a 
                 1989 Nowak U.S. Pat. No. 
               
               
                   
                 print head before 
                 freezes on the 
                 ‘waxy’ feel 
                 4,820,346 
               
               
                   
                 jetting. Hot melt inks 
                 print medium 
                 Printed pages 
                 All IJ series ink jets 
               
               
                   
                 are usually wax 
                 Almost any 
                 may ‘block’ 
               
               
                   
                 based, with a melting 
                 print medium 
                 Ink 
               
               
                   
                 point around 80° C. 
                 can be used 
                 temperature 
               
               
                   
                 After jetting the ink 
                 No paper 
                 may be above 
               
               
                   
                 freezes almost 
                 cockie occurs 
                 the curie point 
               
               
                   
                 instantly upon 
                 No wicking 
                 of permanent 
               
               
                   
                 contacting the print 
                 occurs 
                 magnets 
               
               
                   
                 medium or a transfer 
                 No bleed 
                 Ink heaters 
               
               
                   
                 roller. 
                 occurs 
                 consume 
               
               
                   
                   
                 No 
                 power 
               
               
                   
                   
                 strikethrough 
                 Long warm-up 
               
               
                   
                   
                 occurs 
                 time 
               
               
                 Oil 
                 Oil based inks are 
                 High solubility 
                 High viscosity: 
                 All IJ series ink jets 
               
               
                   
                 extensively used in 
                 medium for 
                 this is a 
               
               
                   
                 offset printing. They 
                 some dyes 
                 significant 
               
               
                   
                 have advantages in 
                 Does not 
                 limitation for 
               
               
                   
                 improved 
                 cockle paper 
                 use in ink jets, 
               
               
                   
                 characteristics on 
                 Does not wick 
                 which usually 
               
               
                   
                 paper (especially no 
                 through paper 
                 require a low 
               
               
                   
                 wicking or cockle). 
                   
                 viscosity. 
               
               
                   
                 Oil soluble dies and 
                   
                 Some short 
               
               
                   
                 pigments are 
                   
                 chain and 
               
               
                   
                 required. 
                   
                 multi-branched 
               
               
                   
                   
                   
                 oils have a 
               
               
                   
                   
                   
                 sufficiently 
               
               
                   
                   
                   
                 low viscosity. 
               
               
                   
                   
                   
                 Slow drying 
               
               
                 Micro- 
                 A microemulsion is a 
                 Stops ink bleed 
                 Viscosity 
                 All IJ series ink jets 
               
               
                 emulsion 
                 stable, self forming 
                 High dye 
                 higher than 
               
               
                   
                 emulsion of Oil, 
                 solubility 
                 water 
               
               
                   
                 water, and surfactant. 
                 Water, oil, and 
                 Cost is slightly 
               
               
                   
                 The characteristic 
                 amphiphilic 
                 higher than 
               
               
                   
                 drop size is less than 
                 soluble dies 
                 water based 
               
               
                   
                 100 nm, and is 
                 can be used 
                 ink 
               
               
                   
                 determined by the 
                 Can stabilize 
                 High surfactant 
               
               
                   
                 preferred curvature of 
                 pigment 
                 concentration 
               
               
                   
                 the surfactant. 
                 suspensions 
                 required 
               
               
                   
                   
                   
                 (around 5%)