Patent Publication Number: US-6217153-B1

Title: Single bend actuator cupped paddle 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, U.S. patent applications identified by their U.S. patent application serial numbers (USSN) are listed alongside the Australian applications from which the US patent applications claim the right of priority. 
     
       
         
           
               
               
               
             
               
                   
               
               
                   
                 US PATENT APPLICATION 
                   
               
               
                 CROSS-REFERENCED 
                 (CLAIMING RIGHT 
               
               
                 AUSTRALIAN 
                 OF PRIORITY 
               
               
                 PROVISIONAL 
                 FROM AUSTRALIAN 
                 DOCKET 
               
               
                 PATENT NO. 
                 PROVISIONAL APPLICATION) 
                 NO. 
               
               
                   
               
             
            
               
                 PO7991 
                 09/113,060 
                 ART01 
               
               
                 PO8505 
                 09/113,070 
                 ART02 
               
               
                 PO7988 
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                 ART03 
               
               
                 PO9395 
                 09/112,748 
                 ART04 
               
               
                 PO8017 
                 09/112,747 
                 ART06 
               
               
                 PO8014 
                 09/112,776 
                 ART07 
               
               
                 PO8025 
                 09/112,750 
                 ART08 
               
               
                 PO8032 
                 09/112,746 
                 ART09 
               
               
                 PO7999 
                 09/112,743 
                 ART10 
               
               
                 PO7998 
                 09/112,742 
                 ART11 
               
               
                 PO8031 
                 09/112,741 
                 ART12 
               
               
                 PO8030 
                 09/112,740 
                 ART13 
               
               
                 PO7997 
                 09/112,739 
                 ART15 
               
               
                 PO7979 
                 09/113,053 
                 ART16 
               
               
                 PO8015 
                 09/112,738 
                 ART17 
               
               
                 PO7978 
                 09/113,067 
                 ART18 
               
               
                 PO7982 
                 09/113,063 
                 ART19 
               
               
                 PO7989 
                 09/113,069 
                 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 
               
               
                 PO7987 
                 09/113,071 
                 ART32 
               
               
                 PO8022 
                 09/112,824 
                 ART33 
               
               
                 PO8497 
                 09/113,090 
                 ART34 
               
               
                 PO8020 
                 09/112,823 
                 ART38 
               
               
                 PO8023 
                 09/113,222 
                 ART39 
               
               
                 PO8504 
                 09/112,786 
                 ART42 
               
               
                 PO8000 
                 09/113,051 
                 ART43 
               
               
                 PO7977 
                 09/112,782 
                 ART44 
               
               
                 PO7934 
                 09/113,056 
                 ART45 
               
               
                 PO7990 
                 09/113,059 
                 ART46 
               
               
                 PO8499 
                 09/113,091 
                 ART47 
               
               
                 PO8502 
                 09/112,753 
                 ART48 
               
               
                 PO7981 
                 09/113,055 
                 ART50 
               
               
                 PO7986 
                 09/113,057 
                 ART51 
               
               
                 PO7983 
                 09/113,054 
                 ART52 
               
               
                 PO8026 
                 09/112,752 
                 ART53 
               
               
                 PO8027 
                 09/112,759 
                 ART54 
               
               
                 PO8028 
                 09/112,757 
                 ART56 
               
               
                 PO9394 
                 09/112,758 
                 ART57 
               
               
                 PO9396 
                 09/113,107 
                 ART58 
               
               
                 PO9397 
                 09/112,829 
                 ART59 
               
               
                 PO9398 
                 09/112,792 
                 ART60 
               
               
                 PO9399 
                 09/112,791 
                 ART61 
               
               
                 PO9400 
                 09/112,790 
                 ART62 
               
               
                 PO9401 
                 09/112,789 
                 ART63 
               
               
                 PO9402 
                 09/112,788 
                 ART64 
               
               
                 PO9403 
                 09/112,795 
                 ART65 
               
               
                 PO9405 
                 09/112,749 
                 ART66 
               
               
                 PP0959 
                 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 
                 09/112,803 
                 IJ04 
               
               
                 PO8047 
                 09/113,097 
                 IJ05 
               
               
                 PO8035 
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                 IJ06 
               
               
                 PO8044 
                 09/113,084 
                 IJ07 
               
               
                 PO8063 
                 09/113,066 
                 IJ08 
               
               
                 PO8057 
                 09/112,778 
                 IJ09 
               
               
                 PO8056 
                 09/112,779 
                 IJ10 
               
               
                 PO8069 
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                 IJ11 
               
               
                 PO8049 
                 09/113,061 
                 IJ12 
               
               
                 PO8036 
                 09/112,818 
                 IJ13 
               
               
                 PO8048 
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                 IJ14 
               
               
                 PO8070 
                 09/112,772 
                 IJ15 
               
               
                 PO8067 
                 09/112,819 
                 IJ16 
               
               
                 PO8001 
                 09/112,815 
                 IJ17 
               
               
                 PO8038 
                 09/113,096 
                 IJ18 
               
               
                 PO8033 
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                 IJ19 
               
               
                 PO8002 
                 09/113,095 
                 IJ20 
               
               
                 PO8068 
                 09/112,808 
                 IJ21 
               
               
                 PO8062 
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                 IJ22 
               
               
                 PO8034 
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                 IJ23 
               
               
                 PO8039 
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                 IJ24 
               
               
                 PO8041 
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                 IJ25 
               
               
                 PO8004 
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                 IJ26 
               
               
                 PO8037 
                 09/112,793 
                 IJ27 
               
               
                 PO8043 
                 09/112,794 
                 IJ28 
               
               
                 PO8042 
                 09/113,128 
                 IJ29 
               
               
                 PO8064 
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                 IJ30 
               
               
                 PO9389 
                 09/112,756 
                 IJ31 
               
               
                 PO9391 
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                 IJ32 
               
               
                 PP0888 
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                 IJ33 
               
               
                 PP0891 
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                 IJ34 
               
               
                 PP0890 
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                 IJ35 
               
               
                 PP0873 
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                 IJ36 
               
               
                 PP0993 
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                 IJ37 
               
               
                 PP0890 
                 09/112,764 
                 IJ38 
               
               
                 PP1398 
                 09/112,765 
                 IJ39 
               
               
                 PP2592 
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                 IJ40 
               
               
                 PP2593 
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                 IJ41 
               
               
                 PP3991 
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                 IJ42 
               
               
                 PP3987 
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                 IJ43 
               
               
                 PP3985 
                 09/112,820 
                 IJ44 
               
               
                 PP3983 
                 09/112,821 
                 IJ45 
               
               
                 PO7935 
                 09/112,822 
                 IJM01 
               
               
                 PO7936 
                 09/112,825 
                 IJM02 
               
               
                 PO7937 
                 09/112,826 
                 IJM03 
               
               
                 PO8061 
                 09/112,827 
                 IJM04 
               
               
                 PO8054 
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                 IJM05 
               
               
                 PO8065 
                 09/113,111 
                 IJM06 
               
               
                 PO8055 
                 09/113,108 
                 IJM07 
               
               
                 PO8053 
                 09/113,109 
                 IJM08 
               
               
                 PO8078 
                 09/113,123 
                 IJM09 
               
               
                 PO7933 
                 09/113,114 
                 IJM10 
               
               
                 PO7950 
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                 IJM11 
               
               
                 PO7949 
                 09/113,129 
                 IJM12 
               
               
                 PO8060 
                 09/113,124 
                 IJM13 
               
               
                 PO8059 
                 09/113,125 
                 IJM14 
               
               
                 PO8073 
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                 IJM15 
               
               
                 PO8076 
                 09/113,119 
                 IJM16 
               
               
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                 IJM17 
               
               
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                 IJM18 
               
               
                 PO8050 
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                 IJM19 
               
               
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                 IJM20 
               
               
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                 IJM21 
               
               
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                 IJM22 
               
               
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                 IJM23 
               
               
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                 IJM24 
               
               
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                 IJM25 
               
               
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                 IJM27 
               
               
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                 IJM28 
               
               
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                 IJM29 
               
               
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                 IJM30 
               
               
                 PO9390 
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                 IJM31 
               
               
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                 IJM32 
               
               
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                 IJM35 
               
               
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                 IJM40 
               
               
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                 IJM41 
               
               
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                 IJM42 
               
               
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                 IJM44 
               
               
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                 IJM45 
               
               
                 PP0895 
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                 IR01 
               
               
                 PP0870 
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                 IR02 
               
               
                 PP0869 
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                 IR04 
               
               
                 PP0887 
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                 IR05 
               
               
                 PP0885 
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                 IR06 
               
               
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                 IR10 
               
               
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                 IR12 
               
               
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                 IR13 
               
               
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                 IR14 
               
               
                 PP0877 
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                 IR16 
               
               
                 PP0878 
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                 IR17 
               
               
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                 IR18 
               
               
                 PP0883 
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                 IR19 
               
               
                 PP0880 
                 09/112,745 
                 IR20 
               
               
                 PP0881 
                 09/113,092 
                 IR21 
               
               
                 PO8006 
                 09/113,100 
                 MEMS02 
               
               
                 PO8007 
                 09/113,093 
                 MEMS03 
               
               
                 PO8008 
                 09/113,062 
                 MEMS04 
               
               
                 PO8010 
                 09/113,064 
                 MEMS05 
               
               
                 PO8011 
                 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 field of the invention relates to the field of inkjet printing devices and in particular, discloses a single bend actuator cupped paddle inkjet printing device. 
     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 printing 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 on ink jet printing have been invented. For a survey of the field, reference is made to an article by J Moore, “Non-Impact Printing: Introduction and Historical Perspective”, Output Hard Copy Devices, Editors R Dubeck and S Sherr, pages 207-220 (1988). 
     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 utilizes a diaphragm mode of operation, by Zolten in U.S. Pat. No. 3,683,212 (1970) which discloses a squeeze mode of operation of a piezoelectric crystal, Stemme in U.S. Pat. No. 3,747,120 (1972) discloses a bend mode of piezoelectric 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 shear 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 disclose ink jet printing techniques rely upon the activation of an electrothermal actuator which results in the creation of a bubble in a constricted space, such as a nozzle, which thereby causes the ejection of ink from an aperture connected to the confined space onto a relevant print media. Printing devices utilizing the electro-thermal actuator are manufactured by manufacturers such as Canon and Hewlett Packard. 
     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. 
     When creating a large number of inkjet nozzles which together form a printhead, it is necessary or desirable to ensure that the printhead is of a compact form so as to ensure that the printhead takes up as small a space as possible. Further, it is desirable that any construction of a printhead is as simple as possible and preferably, the number of steps in construction are extremely low, therefore ensuring simplicity of manufacture. Further, preferably each ink ejection nozzle is of a standard size and the ink forces associates with the ejection are regular across the nozzle. 
     Further, where the ink ejection mechanism is of a mechanical type attached to an actuator device, it is important to ensure that a substantial clearance is provided between an ink ejection nozzle and the surface of the paddle. Unless a large clearance is provided (of the order of 10□m in the case of a 40□m nozzle) a number of consequential problems may arise. For example, if a mechanical paddle ejection surface and nozzle chamber walls are too close, insufficient ink will be acted on by the paddle actuator so as to form a drop to be ejected. Further, high pressures and drag is likely to occur where movement of a paddle occurs close to nozzle chamber walls. Further, if the paddle is too close to the nozzle, there is a danger that an unwanted meniscus shape may occur after ejection of an ink drop with the ink meniscus surface attaching to the surface of the paddle. 
     Further, should the ink ejection mechanism be formed on a silicon wafer type device utilizing standard wafer processing techniques, it is desirable to minimize the thickness of any layer of material when forming the system. Due to differential thermal expansions, it is desirable to ensure each layer is of minimal thickness so as to reduce the likelihood of faults occurring during the fabrication of a printhead system due to thermal stress. Hence, it is desirable to construct a printhead system utilizing thin layers in the construction process. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an alternative form of inkjet printing system. 
     In accordance with a first aspect of the present invention, there is provided an ink jet printing nozzle arrangement including an ink chamber having an ink ejection nozzle in one wall thereof for the ejection of ink from the ink chamber; a moveable paddle vane located within the ink chamber; an actuator means adapted to move the paddle vane so as to cause ink within the ink chamber to be ejected from the ink ejection nozzle; wherein the paddle vane includes a concave surface in the area adjacent the ink ejection nozzle. 
     Preferably, the paddle vane includes a cup shaped surface in the area adjacent the ink ejection nozzle. The nozzle arrangement can be formed utilizing normal micro-electro mechanical construction techniques and the concave surface can be formed as the result of the deposition of a film over a pit. 
     The actuator means can include an actuating portion located externally to the nozzle chamber and operational in an external ambient atmosphere of the arrangement. The ink chamber can further include a slot defined in a wall thereof such that the actuator means communicates with the moveable paddle vane through the slot. 
     The actuator means can comprise a thermal actuator which includes a conductive heater element having a high bend efficiency such that when an electric current is passed through the conductive heater element, the heater element undergoes thermal expansion causing the actuator means to move the paddle towards the ink ejection nozzle. Preferably, the external surfaces of the slot are profiled so as to minimize any wicking of the ink out of the slot. The profile can include a surface having a protruding rim around the slot and the actuator means can be shaped so as to minimize wicking of ink along the actuator means. 
     Further, preferably, the paddle vane includes a slit in a surface thereof to assist in the refill flow of ink into the ink chamber. 
    
    
     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 in which: 
     FIGS. 1-3 are schematic illustrations of the operational principles of the preferred embodiment; 
     FIG. 4 illustrates a perspective view, partly in section of a single inkjet nozzle of the preferred embodiment; 
     FIG. 5 is a side perspective view of a single ink jet nozzle of the preferred embodiment; 
     FIGS. 6-15 illustrate the various manufacturing processing steps in the construction of the preferred embodiment; 
     FIG. 16 illustrates a portion of an array view of a printhead having a large number of nozzles, each constructed in accordance with the principles of the present invention. 
     FIG. 17 provides a legend of the materials indicated in FIGS. 18 to  28 ; and 
     FIG. 18 to FIG. 28 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 inkjet printing system is provided having an ink ejection nozzle arrangement such that a paddle actuator type device is utilized to eject ink from a refillable nozzle chamber. As a result of the construction processes utilized, the paddle is generally of a “cupped” shape. The cup shape provides for the alleviation of a number of the aforementioned problems. The paddle is interconnected to a thermal actuator device which is thermally actuated by means of passing a current through a portion of the thermal actuator, so as to cause the ejection of ink therefrom. Further, the cupped paddle allows for a suitable construction process which does not require the formation of thick surface layers during the process of construction. This means that thermal stresses across a series of devices constructed on a single wafer are minimized. 
     Turning initially to FIGS. 1-3, there will now be explained the operational principles of the preferred embodiment. In FIG. 1 there is illustrated an inkjet nozzle arrangement  1  having a nozzle chamber  2  which is normally filled with ink from a supply channel  3  such that a meniscus  4  forms across the ink ejection aperture of the nozzle arrangement. Inside the nozzle arrangement, a cupped paddle actuator  5  is provided and interconnected to an actuator arm  6  which, when in a quiescent position, is bent downwards. The lower surface of the actuator arm  6  includes a heater element  8  which is constructed of material having a high “bend efficiency”. 
     Preferably, the heater element has a high bend efficiency wherein the bend efficiency is defined as:          bend  efficiency     =         Young   &#39;        s                 Modulus              ×                (     Coefficient                 of                 thermal                 Expansion     )         Density              ×              Specific                 Heat                 Capacity                       
     A suitable material can be a copper nickel alloy of 60% copper and 40% nickel, hereinafter called (cupronickel). Which can be formed below a glass layer so as to bend the glass layer. 
     In its quiescent position, the arm  6  is bent down by the element  8 . When it is desired to eject a droplet of ink from the nozzle chamber  2 , a current is passed through the actuator arm  8  by means of an interconnection provided by a post  9 . The heater element  8  is heated and expands with a high bend efficiency thereby causing the arm  6  to move upwards as indicated in FIG.  2 . The upward movement of the actuator arm  6  causes the cupped paddle  5  to also move up which results in a general increase in pressure within the nozzle chamber  2  in the area surrounding the meniscus  4 . This results in a general outflow of ink and a bulging of the meniscus  4 . Next, as indicated in FIG. 3, the heater element  8  is turned off which results in the general return of the arm  6  to its quiescent position which further results in a downward movement of the cupped paddle  5 . This results in a general sucking back  11  of the ink within the nozzle chamber  2 . The forward momentum of the ink surrounding the meniscus and the backward momentum of the ink results in a general necking of the meniscus and the formation of a drop  12  which proceeds to the surface of the page. Subsequently, the shape of the meniscus  4  results in a subsequent inflow of ink via the inlet channel  3  which results in a refilling of the nozzle chamber  2 . Eventually, the state returns to that indicated by FIG.  1 . 
     Turning now to FIG. 4, there is illustrated a side perspective view partly in section of one form of construction, a single nozzle arrangement  1  in greater detail. The nozzle arrangement  1  includes a nozzle chamber  2  which is normally filled with ink. Inside the nozzle chamber  2  is a paddle actuator  5  which divides the nozzle chamber from an ink refill supply channel  3  which supplies ink from a back surface of a silicon wafer  14 . 
     Outside of the nozzle chamber  2  is located an actuator arm  6  which includes a glass core portion and an external cupronickel portion  8 . The actuator arm  6  interconnects with the paddle  5  by means of a slot  19  located in one wall of the nozzle chamber  2 . The slot  19  is of small dimensions such that surface tension characteristics retain the ink within the nozzle chamber  2 . Preferably, the external portions of the arrangement  1  are further treated so as to be strongly hydrophobic. Additionally, a pit  21  is provided around the slot  19 . The pit includes a ledge  22  with the pit and ledge interacting so as to minimize the opportunities for “wicking” along the actuator arm  6 . Further, to assist of minimizing of wicking, the arm  6  includes a thinned portion  24  adjacent to the nozzle chamber  2  in addition to a right angled wall  25 . 
     The surface of the paddle actuator  5  includes a slot  12 . The slot  12  aids in allowing for the flow of ink from the back surface of paddle actuator  5  to a front surface. This is especially the case when initially the arrangement is filled with air and a liquid is injected into the refill channel  3 . The dimensions of the slot are such that, during operation of the paddle for ejecting drops, minimal flow of fluid occurs through the slot  11 . 
     The paddle actuator  5  is housed within the nozzle chamber and is actuated so as to eject ink from the nozzle  27  which in turn includes a rim  28 . The rim  28  assists in minimizing wicking across the top of the nozzle chamber  2 . 
     The cupronickel element  8  is interconnected through a post portion  9  to a lower CMOS layer  15  which provides for the electrical control of the actuator element. 
     Each nozzle arrangement  1 , can be constructed as part of an array of nozzles on a silicon wafer device and can be constructed from the utilizing semiconductor processing techniques in addition to micro machining and micro fabrication process technology (MEMS) and a full familiarity with these technologies is hereinafter assumed. 
     For a general introduction to a micro-electro mechanical system (MEMS) reference is made to standard proceedings in this field including the proceeding of the SPIE (International Society for Optical Engineering) including volumes 2642 and 2882 which contain the proceedings of recent advances and conferences in this field. 
     Turning initially to FIG. 6 a  and  6   b , in FIG. 6 b  there is shown an initial processing step which utilizes a mask having a region as specified in FIG. 6 a . The initial starting material is preferably a silicon wafer  14  having a standard 0.25 μm CMOS layer  15  which includes drive electronics (not shown), the structure of the drive on electronics being readily apparent to those skilled in the art of CMOS integrated circuit designs. 
     The first step in the construction of a single nozzle is to pattern and etch a pit  28  to a depth of 13 μm using the mask pattern having regions specified  29  as illustrated in FIG. 6 a.    
     Next, as illustrated in FIG. 7 b , a 3 μm layer of the sacrificial material  30  is deposited. The sacrificial material can comprise aluminium. The sacrificial material  30  is then etched utilizing a mask pattern having portions  31  and  32  as indicated at FIG. 7 a.    
     Next, as shown in FIG. 8 b  a very thin 0.1 μm layer of a corrosion barrier material (not shown) (for example, silicon nitride) is deposited and subsequently etched so as to form the heater element  35 . The etch utilizes a third mask having mask regions specified  36  and  37  in FIG. 8 a.    
     Next, as shown intended in FIG. 9 b , a 1.1 μm layer of heater material  39  which can comprise a 60% copper 40% nickel alloy is deposited utilizing a mask having a resultant mask region  40  as illustrated in FIG. 9 a.    
     Next a 0.1 μm corrosion layer is deposited over the surface. The corrosion barrier can again comprise silicon nitride. 
     Next, as illustrated in FIG. 10 b , a 3.4 μm layer of glass  42  is deposited. The glass and nitride can then be etched utilizing a mask as specified  43  in FIG. 10 a . The glass layer  42  includes, as part of the deposition process, a portion  44  which is a result of the deposition process following the lower surface profile. 
     Next, a 6 μm layer of sacrificial material  45  such as aluminium is deposited as indicated in FIG. 11 b . This layer is planarized to approximately 4 μm minimum thickness utilizing a Chemical Mechanical Planarization (CMP) process. Next, the sacrificial material layer is etched utilizing a mask having regions  48 ,  49  as illustrated in FIG. 11 a  so as to form portions of the nozzle wall and post. 
     Next, as illustrated in FIG. 12 b , a 3 μm layer of glass  50  is deposited. The 3 μm layer is patterned and etched to a depth of 1 μm using a mask having a region specified  51  as illustrated in FIG. 12 b  so as to form a nozzle rim. 
     Next, as illustrated in FIG. 13 b  the glass layer is etched utilising a further mask as illustrated in FIG. 12 a  which leaves glass portions eg.  53  to form the nozzle chamber wall and post portion  54 . 
     Next, as illustrated in FIG. 14 b  the backside of the wafer is patterned and etched so as to form an ink supply channel  3 . The mask utilized can have regions  56  as specified in FIG. 14 a . The etch through the backside of the wafer can preferably utilize a high quality deep anisotropic etching system such as that available from Silicon Technology Systems of the United Kingdom. Preferably, the etching process also results in the dicing of the wafer into its separate printheads at the same time. 
     Next, as illustrated in FIG. 15, the sacrificial material can be etched away so as to release the actuator structure. Upon release, the actuator  6  bends downwards due to its release from thermal stresses built up during deposition. The printhead can then be cleaned and mounted in a moulded ink supply system for the supply of ink to the back surface of the wafer. A TAB film for suppling electric control to an edge of the printhead can then be bonded utilizing normal TAB bonding techniques. The surface area can then be hydrophobically treated and finally the ink supply channel and nozzle chamber filled with ink for testing. 
     Hence, as illustrated in FIG. 16, a pagewidth printhead having a repetitive structure  60  can be constructed for full colour printing. FIG. 16 shows a portion of the final printhead structure and includes three separate groupings  61 - 63  with one grouping for each colour and each grouping eg.  63  in turn consisting of two separate rows of inkjet nozzles  65 ,  66  which are spaced apart in an interleaved pattern. The nozzle  65 ,  66  are fired at predetermined times so as to form an output image as would be readily understood by those skilled in the art of construction of inkjet printhead. Each nozzle eg.  68  includes its own actuator arm  69  which, in order to form an extremely compact arrangement, is preferably formed so as to be generally bent with respect to the line perpendicular to the row of nozzles. Preferably, a three colour arrangement is provided which has one of the groups  61 - 63  dedicated to cyan, magenta and another yellow colour printing. Obviously, four colour printing arrangements can be constructed if required. 
     Preferably, at one side a series of bond pads eg.  71  are formed along the side for the insertion of a tape automated bonding (TAB) strip which can be aligned by means of alignment rail eg.  72  which is constructed along one edge of the printhead specifically for this purpose. 
     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  14 , complete drive transistors, data distribution, and timing circuits using a 0.5 micron, one poly, 2 metal CMOS process  15 . This step is shown in FIG.  18 . For clarity, these diagrams may not be to scale, and may not represent a cross section though any single plane of the nozzle. FIG. 17 is a key to representations of various materials in these manufacturing diagrams, and those of other cross referenced ink jet configurations. 
     2. Etch oxide down to silicon or aluminum using Mask  1 . This mask defines the pit underneath the paddle, as well as the edges of the printheads chip. 
     3. Etch silicon to a depth of 8 microns  80  using etched oxide as a mask. The sidewall slope of this etch is not critical (60 to 90 degrees is acceptable), so standard trench etchers can be used. This step is shown in FIG.  19 . 
     4. Deposit 3 microns of sacrificial material  81  (e.g. aluminum or polyimide) 
     5. Etch the sacrificial layer using Mask  3 , defining heater vias  82  and nozzle chamber walls  83 . This step is shown in FIG.  20 . 
     6. Deposit 0.2 microns of heater material  84 , e.g. TiN. 
     7. Etch the heater material using Mask  3 , defining the heater shape. This step is shown in FIG.  21 . 
     8. Wafer probe. All electrical connections are complete at this point, bond pads are accessible, and the chips are not yet separated. 
     9. Deposit 3 microns of PECVD glass  85 . 
     10. Etch glass layer using Mask  4 . This mask defines the nozzle chamber wall, the paddle, and the actuator arm. This step is shown in FIG.  22 . 
     11. Deposit 6 microns of sacrificial material  86 . 
     12. Etch the sacrificial material using Mask  5 . This mask defines the nozzle chamber wall. This step is shown in FIG.  23 . 
     13. Deposit 3 microns of PECVD glass  87 . 
     14. Etch to a depth of (approx.) 1 micron using Mask  6 . This mask defines the nozzle rim  28 . This step is shown in FIG.  24 . 
     15. Etch down to the sacrificial layer using Mask  7 . This mask defines the roof of the nozzle chamber, and the nozzle  27  itself. This step is shown in FIG.  25 . 
     16. Back-etch completely through the silicon wafer (with, for example, an ASE Advanced Silicon Etcher from Surface Technology Systems) using Mask  8 . This mask defines the ink inlets  3  which are etched through the wafer. The wafer is also diced by this etch. This step is shown in FIG.  26 . 
     17. Etch the sacrificial material. The nozzle chambers are cleared, the actuators freed, and the chips are separated by this etch. This step is shown in FIG.  27 . 
     18. Mount the printheads in their packaging, which may be a molded plastic former incorporating ink channels which supply the appropriate color ink to the ink inlets at the back of the wafer. 
     19. Connect the printheads to their interconnect systems. For a low profile connection with minimum disruption of airflow, TAB may be used. Wire bonding may also be used if the printer is to be operated with sufficient clearance to the paper. 
     20. Hydrophobize the front surface of the printheads. 
     21. Fill the completed printheads with ink  88  and test them. A filled nozzle is shown in FIG.  28 . 
     The presently disclosed ink jet printing technology is potentially suited to a wide range of printing system including: colour and monochrome office printers, short run digital printers, high speed digital printers, offset press supplemental printers, low cost scanning printers high speed pagewidth printers, notebook computers with inbuilt pagewidth printers, portable colour and monochrome printers, colour and monochrome copiers, colour and monochrome facsimile machines, combined printer, facsimile and copying machines, label printers, large format plotters, photograph copiers, printers for digital photographic “minilabs”, video printers, portable printers for PDAs, wallpaper printers, indoor sign printers, billboard printers, fabric printers, camera printers and fault tolerant commercial printer arrays. 
     The fully formed printhead being able to be utilised in a wide range of printing systems. 
     It would be appreciated by a person skilled in the art that numerous variations and/or modifications may be made to the present invention as shown in the specific embodiment without departing from the spirit or scope of the invention as broadly described. The present embodiment is, therefore, to be considered in all respects to be illustrative and not restrictive. 
     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 below 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 printhead is connected to the camera circuitry by tape automated bonding. 
     Tables of Drop-on-Demand Ink Jets 
     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 above 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, 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 
               
               
                 bubble 
                 heater heats the ink to 
                 generated 
                 ♦ Ink carrier 
                 1979 Endo et al GB 
               
               
                   
                 above boiling point, 
                 ♦ Simple 
                 limited to water 
                 patent 2,007,162 
               
               
                   
                 transferring significant 
                 construction 
                 ♦ Low efficiency 
                 ♦ Xerox heater-in- 
               
               
                   
                 heat to the aqueous 
                 ♦ No moving parts 
                 ♦ High 
                 pit 1990 Hawkins et 
               
               
                   
                 ink A bubble 
                 ♦ Fast operation 
                 temperatures 
                 al USP 4,899,181 
               
               
                   
                 nucleates and quickly 
                 ♦ Small chip area 
                 required 
                 ♦ Hewlett-Packard 
               
               
                   
                 forms, expelling the 
                 required for actuator 
                 ♦ High mechanical 
                 TIJ 1982 Vaught et 
               
               
                   
                 ink. 
                   
                 stress 
                 al USP 4,490,728 
               
               
                   
                 The efficiency of the 
                   
                 ♦ Unusual 
               
               
                   
                 process is low, with 
                   
                 materials required 
               
               
                   
                 typically less than 
                   
                 ♦ Large drive 
               
               
                   
                 0.05% of the electrical 
                   
                 transistors 
               
               
                   
                 energy being 
                   
                 ♦ Cavitation causes 
               
               
                   
                 transformed into 
                   
                 actuator failure 
               
               
                   
                 kinetic energy of the 
                   
                 ♦ Kogation reduces 
               
               
                   
                 drop. 
                   
                 bubble formation 
               
               
                   
                   
                   
                 ♦ Large print heads 
               
               
                   
                   
                   
                 are difficult to 
               
               
                   
                   
                   
                 fabricate 
               
               
                 Piezo- 
                 A piezoelectric crystal 
                 ♦ Low power 
                 ♦ Very large area 
                 ♦ Kyser et al USP 
               
               
                 electric 
                 such as lead 
                 consumption 
                 required for actuator 
                 3,946,398 
               
               
                   
                 lanthanum zirconate 
                 ♦ Many ink types 
                 ♦ Difficult to 
                 ♦ Zoltan USP 
               
               
                   
                 (PZT) is electrically 
                 can be used 
                 integrate with 
                 3,683,212 
               
               
                   
                 activated, and either 
                 ♦ Fast operation 
                 electronics 
                 ♦ 1973 Stemme 
               
               
                   
                 expands, shears, or 
                 ♦ High efficiency 
                 ♦ High voltage 
                 USP 3,747,120 
               
               
                   
                 bends to apply 
                   
                 drive transistors 
                 ♦ Epson Stylus 
               
               
                   
                 pressure to the ink, 
                   
                 required 
                 ♦ Tektronix 
               
               
                   
                 ejecting drops. 
                   
                 ♦ Full pagewidth 
                 ♦ IJ04 
               
               
                   
                   
                   
                 print heads 
               
               
                   
                   
                   
                 impractical due to 
               
               
                   
                   
                   
                 actuator size 
               
               
                   
                   
                   
                 ♦ Requires 
               
               
                   
                   
                   
                 electrical poling in 
               
               
                   
                   
                   
                 high field strengths 
               
               
                   
                   
                   
                 during manufacture 
               
               
                 Electro- 
                 An electric field is 
                 ♦ Low power 
                 ♦ Low maximum 
                 ♦ Seiko Epson, 
               
               
                 strictive 
                 used to activate 
                 consumption 
                 strain (approx. 
                 Usui et all JP 
               
               
                   
                 electrostriction in 
                 ♦ Many ink types 
                 0.01%) 
                 253401/96 
               
               
                   
                 relaxor materials such 
                 can be used 
                 ♦ Large area 
                 ♦ IJ04 
               
               
                   
                 as lead lanthanum 
                 ♦ Low thermal 
                 required for actuator 
               
               
                   
                 zirconate titanate 
                 expansion 
                 due to low strain 
               
               
                   
                 (PLZT) or lead 
                 ♦ Electric field 
                 ♦ Response speed 
               
               
                   
                 magnesium niobate 
                 strength required 
                 is marginal (˜10 
               
               
                   
                 (PMN). 
                 (approx. 3.5 V/μm) 
                 μs) 
               
               
                   
                   
                 can be generated 
                 ♦ High voltage 
               
               
                   
                   
                 without difficulty 
                 drive transistors 
               
               
                   
                   
                 ♦ Does not require 
                 required 
               
               
                   
                   
                 electrical poling 
                 ♦ Full pagewidth 
               
               
                   
                   
                   
                 print heads 
               
               
                   
                   
                   
                 impractical due to 
               
               
                   
                   
                   
                 actuator size 
               
               
                 Ferro- 
                 An electric field is 
                 ♦ Low power 
                 ♦ Difficult to 
                 ♦ IJ04 
               
               
                 electric 
                 used to induce a phase 
                 consumption 
                 integrate with 
               
               
                   
                 transition between the 
                 ♦ Many ink types 
                 electronics 
               
               
                   
                 antiferroelectric (AFE) 
                 can be used 
                 ♦ Unusual 
               
               
                   
                 and ferroelectric (FE) 
                 ♦ Fast operation 
                 materials such as 
               
               
                   
                 phase. Perovskite 
                 (&lt;1 μs) 
                 PLZSnT are 
               
               
                   
                 materials such as tin 
                 ♦ Relatively high 
                 required 
               
               
                   
                 modified lead 
                 longitudinal strain 
                 ♦ Actuators require 
               
               
                   
                 lanthanum zirconate 
                 ♦ High efficiency 
                 a large area 
               
               
                   
                 titanate (PLZSnT) 
                 ♦ Electric field 
               
               
                   
                 exhibit large strains of 
                 strength of around 3 
               
               
                   
                 up to 1% associated 
                 V/μm can be readily 
               
               
                   
                 with the AFE to FE 
                 provided 
               
               
                   
                 phase transition. 
               
               
                 Electro- 
                 Conductive plates are 
                 ♦ Low power 
                 ♦ Difficult to 
                 ♦ IJ02, IJ04 
               
               
                 static plates 
                 separated by a 
                 consumption 
                 operate electrostatic 
               
               
                   
                 compressible or fluid 
                 ♦ Many ink types 
                 devices in an 
               
               
                   
                 dielectric (usually air). 
                 can be used 
                 aqueous 
               
               
                   
                 Upon application of a 
                 ♦ Fast operation 
                 environment 
               
               
                   
                 voltage, the plates 
                   
                 ♦ The electrostatic 
               
               
                   
                 attract each other and 
                   
                 actuator will 
               
               
                   
                 displace ink, causing 
                   
                 normally need to be 
               
               
                   
                 drop ejection. The 
                   
                 separated from the 
               
               
                   
                 conductive plates may 
                   
                 ink 
               
               
                   
                 be in a comb or 
                   
                 ♦ Very large area 
               
               
                   
                 honeycomb structure, 
                   
                 required to achieve 
               
               
                   
                 or stacked to increase 
                   
                 high forces 
               
               
                   
                 the surface area and 
                   
                 ♦ High voltage 
               
               
                   
                 therefore the force. 
                   
                 drive transistors 
               
               
                   
                   
                   
                 may be required 
               
               
                   
                   
                   
                 ♦ Full pagewidth 
               
               
                   
                   
                   
                 print heads are not 
               
               
                   
                   
                   
                 competitive due to 
               
               
                   
                   
                   
                 actuator size 
               
               
                 Electro- 
                 A strong electric field 
                 ♦ Low current 
                 ♦ High voltage 
                 ♦ 1989 Saito et al, 
               
               
                 static pull 
                 is applied to the ink, 
                 consumption 
                 required 
                 USP 4,799,068 
               
               
                 on ink 
                 whereupon 
                 ♦ low temperature 
                 ♦ May be damaged 
                 ♦ 1989 Miura et al, 
               
               
                   
                 electrostatic attraction 
                   
                 by sparks due to air 
                 USP 4,810,954 
               
               
                   
                 accelerates the ink 
                   
                 breakdown 
                 ♦ Tone-jet 
               
               
                   
                 towards the print 
                   
                 ♦ Required field 
               
               
                   
                 medium. 
                   
                 strength increases as 
               
               
                   
                   
                   
                 the drop size 
               
               
                   
                   
                   
                 decreases 
               
               
                   
                   
                   
                 ♦ High voltage 
               
               
                   
                   
                   
                 drive transistors 
               
               
                   
                   
                   
                 required 
               
               
                   
                   
                   
                 ♦ Electrostatic field 
               
               
                   
                   
                   
                 attracts dust 
               
               
                 Permanent 
                 An electromagnet 
                 ♦ Low power 
                 ♦ Complex 
                 ♦ IJ07, IJ10 
               
               
                 magnet 
                 directly attracts a 
                 consumption 
                 fabrication 
               
               
                 electro- 
                 permanent magnet, 
                 ♦ Many ink types 
                 ♦ Permanent 
               
               
                 magnetic 
                 displacing ink and 
                 can be used 
                 magnetic material 
               
               
                   
                 causing drop ejection. 
                 ♦ Fast operation 
                 such as Neodymium 
               
               
                   
                 Rare earth magnets 
                 ♦ High efficiency 
                 Iron Boron (NdFeB) 
               
               
                   
                 with a field strength 
                 ♦ Easy extension 
                 required. 
               
               
                   
                 around 1 Tesla can be 
                 from single nozzles 
                 ♦ High local 
               
               
                   
                 used. Examples are: 
                 to pagewidth print 
                 currents required 
               
               
                   
                 Samarium Cobalt 
                 heads 
                 ♦ Copper 
               
               
                   
                 (SaCo) and magnetic 
                   
                 metalization should 
               
               
                   
                 materials in the 
                   
                 be used for long 
               
               
                   
                 neodymium iron boron 
                   
                 electromigration 
               
               
                   
                 family (NdFeB, 
                   
                 lifetime and low 
               
               
                   
                 NdDyFeBNb, 
                   
                 resistivity 
               
               
                   
                 NdDyFeB, etc) 
                   
                 ♦ Pigmented inks 
               
               
                   
                   
                   
                 are usually 
               
               
                   
                   
                   
                 infeasible 
               
               
                   
                   
                   
                 ♦ Operating 
               
               
                   
                   
                   
                 temperature limited 
               
               
                   
                   
                   
                 to the Curie 
               
               
                   
                   
                   
                 temperature (around 
               
               
                   
                   
                   
                 540K) 
               
               
                 Soft 
                 A solenoid induced a 
                 ♦ Low power 
                 ♦ Complex 
                 ♦ IJ01, IJ05, IJ08, 
               
               
                 magnetic 
                 magnetic field in a soft 
                 consumption 
                 fabrication 
                 IJ10, IJ12, IJ14, 
               
               
                 core electro- 
                 magnetic core or yoke 
                 ♦ Many ink types 
                 ♦ Materials not 
                 IJ15, IJ17 
               
               
                 magnetic 
                 fabricated from a 
                 can be used 
                 usually present in a 
               
               
                   
                 ferrous material such 
                 ♦ Fast operation 
                 CMOS fab such as 
               
               
                   
                 as electroplated iron 
                 ♦ High efficiency 
                 NiFe, CoNiFe, or 
               
               
                   
                 alloys such as CoNiFe 
                 ♦ Easy extension 
                 CoFe are required 
               
               
                   
                 [1], CoFe, or NiFe 
                 from single nozzles 
                 ♦ High local 
               
               
                   
                 alloys. Typically, the 
                 to pagewidth print 
                 currents required 
               
               
                   
                 soft magnetic material 
                 heads 
                 ♦ Copper 
               
               
                   
                 is in two parts, which 
                 ♦ 
                 metalization should 
               
               
                   
                 are normally held 
                   
                 be used for long 
               
               
                   
                 apart by a spring. 
                   
                 electromigration 
               
               
                   
                 When the solenoid is 
                   
                 lifetime and low 
               
               
                   
                 actuated, the two parts 
                   
                 resistivity 
               
               
                   
                 attract, displacing the 
                   
                 ♦ Electroplating is 
               
               
                   
                 ink. 
                   
                 required 
               
               
                   
                   
                   
                 ♦ High saturation 
               
               
                   
                   
                   
                 flux density is 
               
               
                   
                   
                   
                 required (2.0-2.1 T 
               
               
                   
                   
                   
                 is achievable with 
               
               
                   
                   
                   
                 CoNiFe [1]) 
               
               
                 Lorenz 
                 The Lorenz force 
                 ♦ Low power 
                 ♦ Force acts as a 
                 ♦ IJ06, IJ11, IJ13, 
               
               
                 force 
                 acting on a current 
                 consumption 
                 twisting motion 
                 IJ16 
               
               
                   
                 carrying wire in a 
                 ♦ Many ink types 
                 ♦ Typically, only a 
               
               
                   
                 magnetic field is 
                 can be used 
                 quarter of the 
               
               
                   
                 utilized. 
                 ♦ Fast operation 
                 solenoid length 
               
               
                   
                 This allows the 
                 ♦ High efficiency 
                 provides force in a 
               
               
                   
                 magnetic field to be 
                 ♦ Easy extension 
                 useful direction 
               
               
                   
                 supplied externally to 
                 from single nozzles 
                 ♦ High local 
               
               
                   
                 the print head, for 
                 to pagewidth print 
                 currents required 
               
               
                   
                 example with rare 
                 heads 
                 ♦ Copper 
               
               
                   
                 earth permanent 
                   
                 metalization should 
               
               
                   
                 magnets. 
                   
                 be used for long 
               
               
                   
                 Only the current 
                   
                 electromigration 
               
               
                   
                 carrying wire need be 
                   
                 lifetime and low 
               
               
                   
                 fabricated on the print- 
                   
                 resistivity 
               
               
                   
                 head, simplifying 
                   
                 ♦ Pigmented inks 
               
               
                   
                 materials 
                   
                 are usually 
               
               
                   
                 requirements. 
                   
                 infeasible 
               
               
                 Magneto- 
                 The actuator uses the 
                 ♦ Many ink types 
                 ♦ Force acts as a 
                 ♦ Fischenbeck, 
               
               
                 striction 
                 giant magnetostrictive 
                 can be used 
                 twisting motion 
                 USP 4,032,929 
               
               
                   
                 effect of materials 
                 ♦ Fast operation 
                 ♦ Unusual 
                 ♦ IJ25 
               
               
                   
                 such as Terfenol-D (an 
                 ♦ Easy extension 
                 materials such as 
               
               
                   
                 alloy of terbium, 
                 from single nozzles 
                 Teffenol-D are 
               
               
                   
                 dysprosium and iron 
                 to pagewidth print 
                 required 
               
               
                   
                 developed at the Naval 
                 heads 
                 ♦ High local 
               
               
                   
                 Ordnance Laboratory, 
                 ♦ High force is 
                 currents required 
               
               
                   
                 hence Ter-Fe-NOL). 
                 available 
                 ♦ Copper 
               
               
                   
                 For best efficiency, the 
                   
                 metalization should 
               
               
                   
                 actuator should be pre- 
                   
                 be used for long 
               
               
                   
                 stressed to approx. 8 
                   
                 electromigration 
               
               
                   
                 MPa. 
                   
                 lifetime and low 
               
               
                   
                   
                   
                 resistivity 
               
               
                   
                   
                   
                 ♦ Pre-stressing 
               
               
                   
                   
                   
                 may be required 
               
               
                 Surface 
                 Ink under positive 
                 ♦ Low power 
                 ♦ Requires 
                 ♦ Silverbrook, EP 
               
               
                 tension 
                 pressure is held in a 
                 consumption 
                 supplementary force 
                 0771 658 A2 and 
               
               
                 reduction 
                 nozzle by surface 
                 ♦ Simple 
                 to effect drop 
                 related patent 
               
               
                   
                 tension. The surface 
                 construction 
                 separation 
                 applications 
               
               
                   
                 tension of the ink is 
                 ♦ No unusual 
                 ♦ Requires special 
               
               
                   
                 reduced below the 
                 materials required in 
                 ink surfactants 
               
               
                   
                 bubble threshold, 
                 fabrication 
                 ♦ Speed may be 
               
               
                   
                 causing the ink to 
                 ♦ High efficiency 
                 limited by surfactant 
               
               
                   
                 egress from the 
                 ♦ Easy extension 
                 properties 
               
               
                   
                 nozzle. 
                 from single nozzles 
               
               
                   
                   
                 to pagewidth print 
               
               
                   
                   
                 heads 
               
               
                 Viscosity 
                 The ink viscosity is 
                 ♦ Simple 
                 ♦ Requires 
                 ♦ Silverbrook, EP 
               
               
                 reduction 
                 locally reduced to 
                 construction 
                 supplementary force 
                 0771 658 A2 and 
               
               
                   
                 select which drops are 
                 ♦ No unusual 
                 to effect drop 
                 related patent 
               
               
                   
                 to be ejected. A 
                 materials required in 
                 separation 
                 applications 
               
               
                   
                 viscosity reduction can 
                 fabrication 
                 ♦ Requires special 
               
               
                   
                 be achieved 
                 ♦ Easy extension 
                 ink viscosity 
               
               
                   
                 electrothermally with 
                 from single nozzles 
                 properties 
               
               
                   
                 most inks, but special 
                 to pagewidth print 
                 ♦ High speed is 
               
               
                   
                 inks can be engineered 
                 heads 
                 difficult to achieve 
               
               
                   
                 for a 100:1 viscosity 
                   
                 ♦ Requires 
               
               
                   
                 reduction. 
                   
                 oscillating ink 
               
               
                   
                   
                   
                 pressure 
               
               
                   
                   
                   
                 ♦ A high 
               
               
                   
                   
                   
                 temperature 
               
               
                   
                   
                   
                 difference (typically 
               
               
                   
                   
                   
                 80 degrees) is 
               
               
                   
                   
                   
                 required 
               
               
                 Acoustic 
                 An acoustic wave is 
                 ♦ Can operate 
                 ♦ Complex drive 
                 ♦ 1993 Hadimioglu 
               
               
                   
                 generated and 
                 without a nozzle 
                 circuitry 
                 et al, EUP 550,192 
               
               
                   
                 focussed upon the 
                 plate 
                 ♦ Complex 
                 ♦ 1993 Elrod et al, 
               
               
                   
                 drop ejection region 
                   
                 fabrication 
                 EUP 572,220 
               
               
                   
                   
                   
                 ♦ Low efficiency 
               
               
                   
                   
                   
                 ♦ Poor control of 
               
               
                   
                   
                   
                 drop position 
               
               
                   
                   
                   
                 ♦ Poor control of 
               
               
                   
                   
                   
                 drop volume 
               
               
                 Thermo- 
                 An actuator which 
                 ♦ Low power 
                 ♦ Efficient aqueous 
                 ♦ IJ03, IJ09, IJ17, 
               
               
                 elastic bend 
                 relies upon differential 
                 consumption 
                 operation requires a 
                 IJ18, IJ19, IJ20, 
               
               
                 actuator 
                 thermal expansion 
                 ♦ Many ink types 
                 thermal insulator on 
                 IJ21, IJ22, IJ23, 
               
               
                   
                 upon Joule heating is 
                 can be used 
                 the hot side 
                 IJ24, IJ27, IJ28, 
               
               
                   
                 used. 
                 ♦ Simple planar 
                 ♦ Corrosion 
                 IJ29, IJ30, IJ31, 
               
               
                   
                   
                 fabrication 
                 prevention can be 
                 IJ32, IJ33, IJ34, 
               
               
                   
                   
                 ♦ Small chip area 
                 difficult 
                 IJ35, IJ36, IJ37, 
               
               
                   
                   
                 required for each 
                 ♦ Pigmented inks 
                 IJ38, IJ39, IJ40, 
               
               
                   
                   
                 actuator 
                 may be infeasible, 
                 IJ41 
               
               
                   
                   
                 ♦ Fast operation 
                 as pigment particles 
               
               
                   
                   
                 ♦ High efficiency 
                 may jam the bend 
               
               
                   
                   
                 ♦ CMOS 
                 actuator 
               
               
                   
                   
                 compatible voltages 
               
               
                   
                   
                 and currents 
               
               
                   
                   
                 ♦ Standard MEMS 
               
               
                   
                   
                 processes can be 
               
               
                   
                   
                 used 
               
               
                   
                   
                 ♦ Easy extension 
               
               
                   
                   
                 from single nozzles 
               
               
                   
                   
                 to pagewidth print 
               
               
                   
                   
                 heads 
               
               
                 High CTE 
                 A material with a very 
                 ♦ High force can 
                 ♦ Requires special 
                 ♦ IJ09, IJ17, IJ18, 
               
               
                 thermo- 
                 high coefficient of 
                 be generated 
                 material (e.g. PTFE) 
                 IJ20, IJ21, IJ22, 
               
               
                 elastic 
                 thermal expansion 
                 ♦ Three methods of 
                 ♦ Requires a PTFE 
                 IJ23, IJ24, IJ27, 
               
               
                 actuator 
                 (CTE) such as 
                 PTFE deposition are 
                 deposition process, 
                 IJ28, IJ29, IJ30, 
               
               
                   
                 polytetrafluoroethylene 
                 under development: 
                 which is not yet 
                 IJ31, IJ42, IJ43, 
               
               
                   
                 (PTFE) is used. As 
                 chemical vapor 
                 standard in ULSI 
                 IJ44 
               
               
                   
                 high CTE materials 
                 deposition (CVD), 
                 fabs 
               
               
                   
                 are usually non- 
                 spin coating, and 
                 ♦ PTFE deposition 
               
               
                   
                 conductive, a heater 
                 evaporation 
                 cannot be followed 
               
               
                   
                 fabricated from a 
                 ♦ PTFE is a 
                 with high 
               
               
                   
                 conductive material is 
                 candidate for low 
                 temperature (above 
               
               
                   
                 incorporated. A 50 μm 
                 dielectric constant 
                 350° C.) processing 
               
               
                   
                 long PTFE bend 
                 insulation in ULSI 
                 ♦ Pigmented inks 
               
               
                   
                 actuator with 
                 ♦ Very low power 
                 may be infeasible, 
               
               
                   
                 polysilicon heater and 
                 consumption 
                 as pigment particles 
               
               
                   
                 15 mW power input 
                 ♦ Many ink types 
                 may jam the bend 
               
               
                   
                 can provide 180 μN 
                 can be used 
                 actuator 
               
               
                   
                 force and 10 μm 
                 ♦ Simple planar 
               
               
                   
                 deflection. Actuator 
                 fabrication 
               
               
                   
                 motions include: 
                 ♦ Small chip area 
               
               
                   
                 Bend 
                 required for each 
               
               
                   
                 Push 
                 actuator 
               
               
                   
                 Buckle 
                 ♦ Fast operation 
               
               
                   
                 Rotate 
                 ♦ High efficiency 
               
               
                   
                   
                 ♦ CMOS 
               
               
                   
                   
                 compatible voltages 
               
               
                   
                   
                 and currents 
               
               
                   
                   
                 ♦ Easy extension 
               
               
                   
                   
                 from single nozzles 
               
               
                   
                   
                 to pagewidth print 
               
               
                   
                   
                 heads 
               
               
                 Conduct-ive 
                 A polymer with a high 
                 ♦ High force can 
                 ♦ Requires special 
                 ♦ IJ24 
               
               
                 polymer 
                 coefficient of thermal 
                 be generated 
                 materials 
               
               
                 thermo- 
                 expansion (such as 
                 ♦ Very low power 
                 development (High 
               
               
                 elastic 
                 PTFE) is doped with 
                 consumption 
                 CTE conductive 
               
               
                 actuator 
                 conducting substances 
                 ♦ Many ink types 
                 polymer) 
               
               
                   
                 to increase its 
                 can be used 
                 ♦ Requires a PTFE 
               
               
                   
                 conductivity to about 3 
                 ♦ Simple planar 
                 deposition process, 
               
               
                   
                 orders of magnitude 
                 fabrication 
                 which is not yet 
               
               
                   
                 below that of copper. 
                 ♦ Small chip area 
                 standard in ULSI 
               
               
                   
                 The conducting 
                 required for each 
                 fabs 
               
               
                   
                 polymer expands 
                 actuator 
                 ♦ PTFE deposition 
               
               
                   
                 when resistively 
                 ♦ Fast operation 
                 cannot be followed 
               
               
                   
                 heated. 
                 ♦ High efficiency 
                 with high 
               
               
                   
                 Examples of 
                 ♦ CMOS 
                 temperature (above 
               
               
                   
                 conducting dopants 
                 compatible voltages 
                 350° C.) processing 
               
               
                   
                 include: 
                 and currents 
                 ♦ Evaporation and 
               
               
                   
                 Carbon nanotubes 
                 ♦ Easy extension 
                 CVD deposition 
               
               
                   
                 Metal fibers 
                 from single nozzles 
                 techniques cannot 
               
               
                   
                 Conductive polymers 
                 to pagewidth print 
                 be used 
               
               
                   
                 such as doped 
                 heads 
                 ♦ Pigmented inks 
               
               
                   
                 polythiophene 
                   
                 may be infeasible, 
               
               
                   
                 Carbon granules 
                   
                 as pigment particles 
               
               
                   
                   
                   
                 may jam the bend 
               
               
                   
                   
                   
                 actuator 
               
               
                 Shape 
                 A shape memory alloy 
                 ♦ High force is 
                 ♦ Fatigue limits 
                 ♦ IJ26 
               
               
                 memory 
                 such as TiNi (also 
                 available (stresses 
                 maximum number 
               
               
                 alloy 
                 known as Nitinol- 
                 of hundreds of MPa) 
                 of cycles 
               
               
                   
                 Nickel Titanium alloy 
                 ♦ Large strain is 
                 ♦ Low strain (1%) 
               
               
                   
                 developed at the Naval 
                 available (more than 
                 is required to extend 
               
               
                   
                 Ordnance Laboratory) 
                 3%) 
                 fatigue resistance 
               
               
                   
                 is thermally switched 
                 ♦ High corrosion 
                 ♦ Cycle rate 
               
               
                   
                 between its weak 
                 resistance 
                 limited by heat 
               
               
                   
                 martensitic state and 
                 ♦ Simple 
                 removal 
               
               
                   
                 its high stiffness 
                 construction 
                 ♦ Requires unusual 
               
               
                   
                 austenic state. The 
                 ♦ Easy extension 
                 materials (TiNi) 
               
               
                   
                 shape of the actuator 
                 from single nozzles 
                 ♦ The latent heat of 
               
               
                   
                 in its martensitic state 
                 to pagewidth print 
                 transformation must 
               
               
                   
                 is deformed relative to 
                 heads 
                 be provided 
               
               
                   
                 the austenic shape. 
                 ♦ Low voltage 
                 ♦ High current 
               
               
                   
                 The shape change 
                 operation 
                 operation 
               
               
                   
                 causes ejection of a 
                   
                 ♦ Requires pre- 
               
               
                   
                 drop. 
                   
                 stressing to distort 
               
               
                   
                   
                   
                 the martensitic state 
               
               
                 Linear 
                 Linear magnetic 
                 ♦ Linear Magnetic 
                 ♦ Requires unusual 
                 ♦ IJ12 
               
               
                 Magnetic 
                 actuators include the 
                 actuators can be 
                 semiconductor 
               
               
                 Actuator 
                 Linear Induction 
                 constructed with 
                 materials such as 
               
               
                   
                 Actuator (LIA), Linear 
                 high thrust, long 
                 soft magnetic alloys 
               
               
                   
                 Permanent Magnet 
                 travel, and high 
                 (e.g. CoNiFe) 
               
               
                   
                 Synchronous Actuator 
                 efficiency using 
                 ♦ Some varieties 
               
               
                   
                 (LPMSA), Linear 
                 planar 
                 also require 
               
               
                   
                 Reluctance 
                 semiconductor 
                 permanent magnetic 
               
               
                   
                 Synchronous Actuator 
                 fabrication 
                 materials such as 
               
               
                   
                 (LRSA), Linear 
                 techniques 
                 Neodymium iron 
               
               
                   
                 Switched Reluctance 
                 ♦ Long actuator 
                 boron (NdFeB) 
               
               
                   
                 Actuator (LSRA), and 
                 travel is available 
                 ♦ Requires 
               
               
                   
                 the Linear Stepper 
                 ♦ Medium force is 
                 complex multi- 
               
               
                   
                 Actuator (LSA). 
                 available 
                 phase drive circuitry 
               
               
                   
                   
                 ♦ Low voltage 
                 ♦ High current 
               
               
                   
                   
                 operation 
                 operation 
               
            
           
           
               
            
               
                 BASIC OPERATION MODE 
               
            
           
           
               
               
               
               
               
            
               
                 Actuator 
                 This is the simplest 
                 ♦ Simple operation 
                 ♦ Drop repetition 
                 ♦ Thermal ink jet 
               
               
                 directly 
                 mode of operation: the 
                 ♦ No external 
                 rate is usually 
                 ♦ Piezoelectric ink 
               
               
                 pushes ink 
                 actuator directly 
                 fields required 
                 limited to around 10 
                 jet 
               
               
                   
                 supplies sufficient 
                 ♦ Satellite drops 
                 kHz. However, this 
                 ♦ IJ01, IJ02, IJ03, 
               
               
                   
                 kinetic energy to expel 
                 can be avoided if 
                 is not fundamental 
                 IJ04, IJ05, IJ06, 
               
               
                   
                 the drop. The drop 
                 drop velocity is less 
                 to the method, but is 
                 IJ07, IJ09, IJ11, 
               
               
                   
                 must have a sufficient 
                 than 4 m/s 
                 related to the refill 
                 IJ12, IJ14, IJ16, 
               
               
                   
                 velocity to overcome 
                 ♦ Can be efficient, 
                 method normally 
                 IJ20, IJ22, IJ23, 
               
               
                   
                 the surface tension. 
                 depending upon the 
                 used 
                 IJ24, IJ25, IJ26, 
               
               
                   
                   
                 actuator used 
                 ♦ All of the drop 
                 IJ27, IJ28, IJ29, 
               
               
                   
                   
                   
                 kinetic energy must 
                 IJ30, IJ31, IJ32, 
               
               
                   
                   
                   
                 be provided by the 
                 IJ33, IJ34, IJ35, 
               
               
                   
                   
                   
                 actuator 
                 IJ36, IJ37, IJ38, 
               
               
                   
                   
                   
                 ♦ Satellite drops 
                 IJ39, IJ40, IJ41, 
               
               
                   
                   
                   
                 usually form if drop 
                 IJ42, IJ43, IJ44 
               
               
                   
                   
                   
                 velocity is greater 
               
               
                   
                   
                   
                 than 4.5 m/s 
               
               
                 Proximity 
                 The drops to be 
                 ♦ Very simple print 
                 ♦ Requires close 
                 ♦ Silverbrook, EP 
               
               
                   
                 printed are selected by 
                 head fabrication can 
                 proximity between 
                 0771 658 A2 and 
               
               
                   
                 some manner (e.g. 
                 be used 
                 the print head and 
                 related patent 
               
               
                   
                 thermally induced 
                 ♦ The drop 
                 the print media or 
                 applications 
               
               
                   
                 surface tension 
                 selection means 
                 transfer roller 
               
               
                   
                 reduction of 
                 does not need to 
                 ♦ May require two 
               
               
                   
                 pressurized ink). 
                 provide the energy 
                 print heads printing 
               
               
                   
                 Selected drops are 
                 required to separate 
                 alternate rows of the 
               
               
                   
                 separated from the ink 
                 the drop from the 
                 image 
               
               
                   
                 in the nozzle by 
                 nozzle 
                 ♦ Monolithic color 
               
               
                   
                 contact with the print 
                   
                 print heads are 
               
               
                   
                 medium or a transfer 
                   
                 difficult 
               
               
                   
                 roller. 
               
               
                 Electro- 
                 The drops to be 
                 ♦ Very simple print 
                 ♦ Requires very 
                 ♦ Silverbrook, EP 
               
               
                 static pull 
                 printed are selected by 
                 head fabrication can 
                 high electrostatic 
                 0771 658 A2 and 
               
               
                 on ink 
                 some manner (e.g. 
                 be used 
                 field 
                 related patent 
               
               
                   
                 thermally induced 
                 ♦ The drop 
                 ♦ Electrostatic field 
                 applications 
               
               
                   
                 surface tension 
                 selection means 
                 for small nozzle 
                 ♦ Tone-Jet 
               
               
                   
                 reduction of 
                 does not need to 
                 sizes is above air 
               
               
                   
                 pressurized ink). 
                 provide the energy 
                 breakdown 
               
               
                   
                 Selected drops are 
                 required to separate 
                 ♦ Electrostatic field 
               
               
                   
                 separated from the ink 
                 the drop from the 
                 may attract dust 
               
               
                   
                 in the nozzle by a 
                 nozzle 
               
               
                   
                 strong electric field. 
               
               
                 Magnetic 
                 The drops to be 
                 ♦ Very simple print 
                 ♦ Requires 
                 ♦ Silverbrook, EP 
               
               
                 pull on ink 
                 printed are selected by 
                 head fabrication can 
                 magnetic ink 
                 0771 658 A2 and 
               
               
                   
                 some manner (e.g. 
                 be used 
                 ♦ Ink colors other 
                 related patent 
               
               
                   
                 thermally induced 
                 ♦ The drop 
                 than black are 
                 applications 
               
               
                   
                 surface tension 
                 selection means 
                 difficult 
               
               
                   
                 reduction of 
                 does not need to 
                 ♦ Requires very 
               
               
                   
                 pressurized ink). 
                 provide the energy 
                 high magnetic fields 
               
               
                   
                 Selected drops are 
                 required to separate 
               
               
                   
                 separated from the ink 
                 the drop from the 
               
               
                   
                 in the nozzle by a 
                 nozzle 
               
               
                   
                 strong magnetic field 
               
               
                   
                 acting on the magnetic 
               
               
                   
                 ink. 
               
               
                 Shutter 
                 The actuator moves a 
                 ♦ High speed (&gt;50 
                 ♦ Moving parts are 
                 ♦ IJ13, IJ17, IJ21 
               
               
                   
                 shutter to block ink 
                 kHz) operation can 
                 required 
               
               
                   
                 flow to the nozzle. The 
                 be achieved due to 
                 ♦ Requires ink 
               
               
                   
                 ink pressure is pulsed 
                 reduced refill time 
                 pressure modulator 
               
               
                   
                 at a multiple of the 
                 ♦ Drop timing can 
                 ♦ Friction and wear 
               
               
                   
                 drop ejection 
                 be very accurate 
                 must be considered 
               
               
                   
                 frequency. 
                 ♦ The actuator 
                 ♦ Stiction is 
               
               
                   
                   
                 energy can be very 
                 possible 
               
               
                   
                   
                 low 
               
               
                 Shuttered 
                 The actuator moves a 
                 ♦ Actuators with 
                 ♦ Moving parts are 
                 ♦ IJ08, IJ15, IJ18, 
               
               
                 grill 
                 shutter to block ink 
                 small travel can be 
                 required 
                 IJ19 
               
               
                   
                 flow through a grill to 
                 used 
                 ♦ Requires ink 
               
               
                   
                 the nozzle. The shutter 
                 ♦ Actuators with 
                 pressure modulator 
               
               
                   
                 movement need only 
                 small force can be 
                 ♦ Friction and wear 
               
               
                   
                 be equal to the width 
                 used 
                 must be considered 
               
               
                   
                 of the grill holes. 
                 ♦ High speed (&gt;50 
                 ♦ Stiction is 
               
               
                   
                   
                 kHz) operation can 
                 possible 
               
               
                   
                   
                 be achieved 
               
               
                 Pulsed 
                 A pulsed magnetic 
                 ♦ Extremely low 
                 ♦ Requires an 
                 ♦ IJ10 
               
               
                 magnetic 
                 field attracts an ‘ink 
                 energy operation is 
                 external pulsed 
               
               
                 pull on ink 
                 pusher’ at the drop 
                 possible 
                 magnetic field 
               
               
                 pusher 
                 ejection frequency. An 
                 ♦ No heat 
                 ♦ Requires special 
               
               
                   
                 actuator controls a 
                 dissipation 
                 materials for both 
               
               
                   
                 catch, which prevents 
                 problems 
                 the actuator and the 
               
               
                   
                 the ink pusher from 
                   
                 ink pusher 
               
               
                   
                 moving when a drop is 
                   
                 ♦ Complex 
               
               
                   
                 not to be ejected. 
                   
                 construction 
               
            
           
           
               
            
               
                 AUXILIARY MECHANISM (APPLIED TO ALL NOZZLES) 
               
            
           
           
               
               
               
               
               
            
               
                 None 
                 The actuator directly 
                 ♦ Simplicity of 
                 ♦ Drop ejection 
                 ♦ Most ink jets, 
               
               
                   
                 fires the ink drop, and 
                 construction 
                 energy must be 
                 including 
               
               
                   
                 there is no external 
                 ♦ Simplicity of 
                 supplied by 
                 piezoelectric and 
               
               
                   
                 field or other 
                 operation 
                 individual nozzle 
                 thermal bubble. 
               
               
                   
                 mechanism required. 
                 ♦ Small physical 
                 actuator 
                 ♦ IJ01, IJ02, IJ03, 
               
               
                   
                   
                 size 
                   
                 IJ04, IJ05, IJ07, 
               
               
                   
                   
                   
                   
                 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 
               
               
                 ink pressure 
                 oscillates, providing 
                 pressure can provide 
                 ink pressure 
                 0771 658 A2 and 
               
               
                 (including 
                 much of the drop 
                 a refill pulse, 
                 oscillator 
                 related patent 
               
               
                 acoustic 
                 ejection energy. The 
                 allowing higher 
                 ♦ Ink pressure 
                 applications 
               
               
                 stimul- 
                 actuator selects which 
                 operating speed 
                 phase and amplitude 
                 ♦ IJ08, IJ13, IJ15, 
               
               
                 ation) 
                 drops are to be fired 
                 ♦ The actuators 
                 must be carefully 
                 IJ17, IJ18, IJ19, 
               
               
                   
                 by selectively 
                 may operate with 
                 controlled 
                 IJ21 
               
               
                   
                 blocking or enabling 
                 much lower energy 
                 ♦ Acoustic 
               
               
                   
                 nozzles. The ink 
                 ♦ Acoustic lenses 
                 reflections in the ink 
               
               
                   
                 pressure oscillation 
                 can be used to focus 
                 chamber must be 
               
               
                   
                 may be achieved by 
                 the sound on the 
                 designed for 
               
               
                   
                 vibrating the print 
                 nozzles 
               
               
                   
                 head, or preferably by 
               
               
                   
                 an actuator in the ink 
               
               
                   
                 supply. 
               
               
                 Media 
                 The print head is 
                 ♦ Low power 
                 ♦ Precision 
                 ♦ Silverbrook, EP 
               
               
                 proximity 
                 placed in close 
                 ♦ High accuracy 
                 assembly required 
                 0771 658 A2 and 
               
               
                   
                 proximity to the print 
                 ♦ Simple print head 
                 ♦ Paper fibers may 
                 related patent 
               
               
                   
                 medium. Selected 
                 construction 
                 cause problems 
                 applications 
               
               
                   
                 drops protrude from 
                   
                 ♦ Cannot print on 
               
               
                   
                 the 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 a 
                 ♦ High accuracy 
                 ♦ Bulky 
                 ♦ Silverbrook, EP 
               
               
                 roller 
                 transfer roller instead 
                 ♦ Wide range of 
                 ♦ Expensive 
                 0771 658 A2 and 
               
               
                   
                 of straight to the print 
                 print substrates can 
                 ♦ Complex 
                 related patent 
               
               
                   
                 medium. A transfer 
                 be used 
                 construction 
                 applications 
               
               
                   
                 roller can also be used 
                 ♦ Ink can be dried 
                   
                 ♦ Tektronix hot 
               
               
                   
                 for proximity drop 
                 on the transfer roller 
                   
                 melt piezoelectric 
               
               
                   
                 separation. 
                   
                   
                 ink jet 
               
               
                   
                   
                   
                   
                 ♦ Any of the IJ 
               
               
                   
                   
                   
                   
                 series 
               
               
                 Electro- 
                 An electric field is 
                 ♦ Low power 
                 ♦ Field strength 
                 ♦ Silverbrook, EP 
               
               
                 static 
                 used to accelerate 
                 ♦ Simple print head 
                 required for 
                 0771 658 A2 and 
               
               
                   
                 selected drops towards 
                 construction 
                 separation of small 
                 related patent 
               
               
                   
                 the print medium. 
                   
                 drops is near or 
                 applications 
               
               
                   
                   
                   
                 above air 
                 ♦ Tone-Jet 
               
               
                   
                   
                   
                 breakdown 
               
               
                 Direct 
                 A magnetic field is 
                 ♦ Low power 
                 ♦ Requires 
                 ♦ Silverbrook, EP 
               
               
                 magnetic 
                 used to accelerate 
                 ♦ Simple print head 
                 magnetic ink 
                 0771 658 A2 and 
               
               
                 field 
                 selected drops of 
                 construction 
                 ♦ Requires strong 
                 related patent 
               
               
                   
                 magnetic ink towards 
                   
                 magnetic field 
                 applications 
               
               
                   
                 the print medium. 
                   
               
               
                 Cross 
                 The print head is 
                 ♦ Does not require 
                 ♦ Requires external 
                 ♦ IJ06, IJ16 
               
               
                 magnetic 
                 placed in a constant 
                 magnetic materials 
                 magnet 
               
               
                 field 
                 magnetic field. The 
                 to be integrated in 
                 ♦ Current densities 
               
               
                   
                 Lorenz force in a 
                 the print head 
                 may be high, 
               
               
                   
                 current carrying wire 
                 manufacturing 
                 resulting in 
               
               
                   
                 is used to move the 
                 process 
                 electromigration 
               
               
                   
                 actuator. 
                   
                 problems 
               
               
                 Pulsed 
                 A pulsed magnetic 
                 ♦ Very low power 
                 ♦ Complex print 
                 ♦ IJ10 
               
               
                 magnetic 
                 field is used to 
                 operation is possible 
                 head construction 
               
               
                 field 
                 cyclically attract a 
                 ♦ Small print head 
                 ♦ Magnetic 
               
               
                   
                 paddle, which pushes 
                 size 
                 materials required in 
               
               
                   
                 on the ink. A small 
                   
                 print head 
               
               
                   
                 actuator moves a 
               
               
                   
                 catch, which 
               
               
                   
                 selectively prevents 
               
               
                   
                 the paddle from 
               
               
                   
                 moving. 
               
            
           
           
               
            
               
                 ACTUATOR AMPLIFICATION OR MODIFICATION METHOD 
               
            
           
           
               
               
               
               
               
            
               
                 None 
                 No actuator 
                 ♦ Operational 
                 ♦ Many actuator 
                 ♦ Thermal Bubble 
               
               
                   
                 mechanical 
                 simplicity 
                 mechanisms have 
                 Ink jet 
               
               
                   
                 ampliflcation is used. 
                   
                 insufficient travel, 
                 ♦ IJ01, IJ02, IJ06, 
               
               
                   
                 The actuator directly 
                   
                 or insufficient force, 
                 IJ07, IJ16, IJ25, 
               
               
                   
                 drives the drop 
                   
                 to efficiently drive 
                 IJ26 
               
               
                   
                 ejection process. 
                   
                 the drop ejection 
               
               
                   
                   
                   
                 process 
               
               
                 Differential 
                 An actuator material 
                 ♦ Provides greater 
                 ♦ High stresses are 
                 ♦ Piezoelectric 
               
               
                 expansion 
                 expands more on one 
                 travel in a reduced 
                 involved 
                 ♦ IJ03, IJ09, IJ17, 
               
               
                 bend 
                 side than on the other. 
                 print head area 
                 ♦ Care must be 
                 IJ18, IJ19, IJ20, 
               
               
                 actuator 
                 The expansion may be 
                   
                 taken that the 
                 IJ21, IJ22, IJ23, 
               
               
                   
                 thermal, piezoelectric, 
                   
                 materials do not 
                 IJ24, IJ27, IJ29, 
               
               
                   
                 magnetostrictive, or 
                   
                 delaminate 
                 IJ30, IJ31, IJ32, 
               
               
                   
                 other mechanism. The 
                   
                 ♦ Residual bend 
                 IJ33, IJ34, IJ35, 
               
               
                   
                 bend actuator converts 
                   
                 resulting from high 
                 IJ36, IJ37, IJ38, 
               
               
                   
                 a high force low travel 
                   
                 temperature or high 
                 IJ39, IJ42, IJ43, 
               
               
                   
                 actuator mechanism to 
                   
                 stress during 
                 IJ44 
               
               
                   
                 high travel, lower 
                   
                 formation 
               
               
                   
                 force mechanism. 
               
               
                 Transient 
                 A trilayer bend 
                 ♦ Very good 
                 ♦ High stresses are 
                 ♦ IJ40, IJ41 
               
               
                 bend 
                 actuator where the two 
                 temperature stability 
                 involved 
               
               
                 actuator 
                 outside layers are 
                 ♦ High speed, as a 
                 ♦ Care must be 
               
               
                   
                 identical. This cancels 
                 new drop can be 
                 taken that the 
               
               
                   
                 bend due to ambient 
                 fired before heat 
                 materials do not 
               
               
                   
                 temperature and 
                 dissipates 
                 delaminate 
               
               
                   
                 residual stress. The 
                 ♦ Cancels residual 
               
               
                   
                 actuator only responds 
                 stress of formation 
               
               
                   
                 to transient heating of 
               
               
                   
                 one side or the other. 
               
               
                 Reverse 
                 The actuator loads a 
                 ♦ Better coupling 
                 ♦ Fabrication 
                 ♦ IJ05, IJ11 
               
               
                 spring 
                 spring. When the 
                 to the ink 
                 complexity 
               
               
                   
                 actuator is turned off, 
                   
                 ♦ High stress in the 
               
               
                   
                 the spring releases. 
                   
                 spring 
               
               
                   
                 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 
               
               
                 stack 
                 actuators are stacked. 
                 ♦ Reduced drive 
                 fabrication 
                 piezoelectric ink jets 
               
               
                   
                 This can be 
                 voltage 
                 complexity 
                 ♦ IJ04 
               
               
                   
                 appropriate where 
                   
                 ♦ Increased 
               
               
                   
                 actuators require high 
                   
                 possibility of short 
               
               
                   
                 electric field strength, 
                   
                 circuits due to 
               
               
                   
                 such as electrostatic 
                   
                 pinholes 
               
               
                   
                 and piezoelectric 
               
               
                   
                 actuators. 
               
               
                 Multiple 
                 Multiple smaller 
                 ♦ Increases the 
                 ♦ Actuator forces 
                 ♦ IJ12, IJ13, IJ18, 
               
               
                 actuators 
                 actuators are used 
                 force available from 
                 may not add 
                 IJ20, IJ22, IJ28, 
               
               
                   
                 simultaneously to 
                 an actuator 
                 linearly, reducing 
                 IJ42, IJ43 
               
               
                   
                 move the ink. Each 
                 ♦ Multiple 
                 efficiency 
               
               
                   
                 actuator need provide 
                 actuators can be 
               
               
                   
                 only a portion of the 
                 positioned to control 
               
               
                   
                 force required. 
                 ink flow accurately 
               
               
                 Linear 
                 A linear spring is used 
                 ♦ Matches low 
                 ♦ Requires print 
                 ♦ IJ15 
               
               
                 Spring 
                 to transform a motion 
                 travel actuator with 
                 head area for the 
               
               
                   
                 with small travel and 
                 higher travel 
                 spring 
               
               
                   
                 high force into a 
                 requirements 
               
               
                   
                 longer travel, lower 
                 ♦ Non-contact 
               
               
                   
                 force motion. 
                 method of motion 
               
               
                   
                   
                 transformation 
               
               
                 Coiled 
                 A bend actuator is 
                 ♦ Increases travel 
                 ♦ Generally 
                 ♦ IJ17, IJ21, IJ34, 
               
               
                 actuator 
                 coiled to provide 
                 ♦ Reduces chip 
                 restricted to planar 
                 IJ35 
               
               
                   
                 greater travel in a 
                 area 
                 implementations 
               
               
                   
                 reduced chip area. 
                 ♦ Planar 
                 due to extreme 
               
               
                   
                   
                 implementations are 
                 fabrication difficulty 
               
               
                   
                   
                 relatively easy to 
                 in other orientations. 
               
               
                   
                   
                 fabricate. 
               
               
                 Flexure 
                 A bend actuator has a 
                 ♦ Simple means of 
                 ♦ Care must be 
                 ♦ IJ10, IJ19, IJ33 
               
               
                 bend 
                 small region near the 
                 increasing travel of 
                 taken not to exceed 
               
               
                 actuator 
                 fixture point, which 
                 a bend actuator 
                 the elastic limit in 
               
               
                   
                 flexes much more 
                   
                 the flexure area 
               
               
                   
                 readily than the 
                   
                 ♦ Stress 
               
               
                   
                 remainder of the 
                   
                 distribution is very 
               
               
                   
                 actuator. The actuator 
                   
                 uneven 
               
               
                   
                 flexing is effectively 
                   
                 ♦ Difficult to 
               
               
                   
                 converted from an 
                   
                 accurately model 
               
               
                   
                 even coiling to an 
                   
                 with finite element 
               
               
                   
                 angular bend, resulting 
                   
                 analysis 
               
               
                   
                 in greater travel of the 
               
               
                   
                 actuator tip. 
               
               
                 Catch 
                 The actuator controls a 
                 ♦ Very low 
                 ♦ Complex 
                 ♦ IJ10 
               
               
                   
                 small catch. The catch 
                 actuator energy 
                 construction 
               
               
                   
                 either enables or 
                 ♦ Very small 
                 ♦ Requires external 
               
               
                   
                 disables movement of 
                 actuator size 
                 force 
               
               
                   
                 an ink pusher that is 
                   
                 ♦ Unsuitable for 
               
               
                   
                 controlled in a bulk 
                   
                 pigmented inks 
               
               
                   
                 manner. 
               
               
                 Gears 
                 Gears can be used to 
                 ♦ Low force, low 
                 ♦ Moving parts are 
                 ♦ IJ13 
               
               
                   
                 increase travel at the 
                 travel actuators can 
                 required 
               
               
                   
                 expense of duration. 
                 be used 
                 ♦ Several actuator 
               
               
                   
                 Circular gears, rack 
                 ♦ Can be fabricated 
                 cycles are required 
               
               
                   
                 and pinion, ratchets, 
                 using standard 
                 ♦ More complex 
               
               
                   
                 and other gearing 
                 surface MEMS 
                 drive electronics 
               
               
                   
                 methods can be used. 
                 processes 
                 ♦ Complex 
               
               
                   
                   
                   
                 construction 
               
               
                   
                   
                   
                 ♦ Friction, friction, 
               
               
                   
                   
                   
                 and wear are 
               
               
                   
                   
                   
                 possible 
               
               
                 Buckle plate 
                 A buckle plate can be 
                 ♦ Very fast 
                 ♦ Must stay within 
                 ♦ S. Hirata et al, 
               
               
                   
                 used to change a slow 
                 movement 
                 elastic limits of the 
                 “An Ink-jet Head 
               
               
                   
                 actuator into a fast 
                 achievable 
                 materials for long 
                 Using Diaphragm 
               
               
                   
                 motion. It can also 
                   
                 device life 
                 Microactuator”, 
               
               
                   
                 convert a high force, 
                   
                 ♦ High stresses 
                 Proc. IEEE MEMS, 
               
               
                   
                 low travel actuator 
                   
                 involved 
                 Feb. 1996, pp 418- 
               
               
                   
                 into a high travel, 
                   
                 ♦ Generally high 
                 423. 
               
               
                   
                 medium force motion. 
                   
                 power requirement 
                 ♦ IJ18, IJ27 
               
               
                 Tapered 
                 A tapered magnetic 
                 ♦ Linearizes the 
                 ♦ Complex 
                 ♦ IJ14 
               
               
                 magnetic 
                 pole can increase 
                 magnetic 
                 construction 
               
               
                 pole 
                 travel at the expense 
                 force/distance curve 
               
               
                   
                 of force. 
               
               
                 Lever 
                 A lever and fulcrum is 
                 ♦ Matches low 
                 ♦ High stress 
                 ♦ IJ32, IJ36, IJ37 
               
               
                   
                 used to transform a 
                 travel actuator with 
                 around the fulcrum 
               
               
                   
                 motion with small 
                 higher travel 
               
               
                   
                 travel and high force 
                 requirements 
               
               
                   
                 into a motion with 
                 ♦ Fulcrum area has 
               
               
                   
                 longer travel and 
                 no linear movement, 
               
               
                   
                 lower force. The lever 
                 and can be used for 
               
               
                   
                 can also reverse the 
                 a fluid seal 
               
               
                   
                 direction of travel. 
               
               
                 Rotary 
                 The actuator is 
                 ♦ High mechanical 
                 ♦ Complex 
                 ♦ IJ28 
               
               
                 impeller 
                 connected to a rotary 
                 advantage 
                 construction 
               
               
                   
                 impeller. A small 
                 ♦ The ratio of force 
                 ♦ Unsuitable for 
               
               
                   
                 angular deflection of 
                 to travel of the 
                 pigmented inks 
               
               
                   
                 the actuator results in 
                 actuator can be 
               
               
                   
                 a rotation of the 
                 matched to the 
               
               
                   
                 impeller vanes, which 
                 nozzle requirements 
               
               
                   
                 push the ink against 
                 by varying the 
               
               
                   
                 stationary vanes and 
                 number of impeller 
               
               
                   
                 out of the nozzle. 
                 vanes 
               
               
                 Acoustic 
                 A refractive or 
                 ♦ No moving parts 
                 ♦ Large area 
                 ♦ 1993 Hadimioglu 
               
               
                 lens 
                 diffractive (e.g. zone 
                   
                 required 
                 et al, EUP 550,192 
               
               
                   
                 plate) acoustic lens is 
                   
                 ♦ Only relevant for 
                 ♦ 1993 Elrod et al, 
               
               
                   
                 used to concentrate 
                   
                 acoustic ink jets 
                 EUP 572,220 
               
               
                   
                 sound waves. 
               
               
                 Sharp 
                 A sharp point is used 
                 ♦ Simple 
                 ♦ Difficult to 
                 ♦ Tone-jet 
               
               
                 conductive 
                 to concentrate an 
                 construction 
                 fabricate using 
               
               
                 point 
                 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 
               
               
                 expansion 
                 actuator changes, 
                 construction in the 
                 typically required to 
                 Thermal Ink jet 
               
               
                   
                 pushing the ink in all 
                 case of thermal ink 
                 achieve volume 
                 ♦ Canon Bubblejet 
               
               
                   
                 directions. 
                 jet 
                 expansion. This 
               
               
                   
                   
                   
                 leads to thermal 
               
               
                   
                   
                   
                 stress, cavitation, 
               
               
                   
                   
                   
                 and kogation in 
               
               
                   
                   
                   
                 thermal ink jet 
               
               
                   
                   
                   
                 implementations 
               
               
                 Linear, 
                 The actuator moves in 
                 ♦ Efficient 
                 ♦ High fabrication 
                 ♦ IJ01, IJ02, IJ04, 
               
               
                 normal to 
                 a direction normal to 
                 coupling to ink 
                 complexity may be 
                 IJ07, IJ11, IJ14 
               
               
                 chip surface 
                 the print head surface. 
                 drops ejected 
                 required to achieve 
               
               
                   
                 The nozzle is typically 
                 normal to the 
                 perpendicular 
               
               
                   
                 in the line of 
                 surface 
                 motion 
               
               
                   
                 movement. 
               
               
                 Parallel to 
                 The actuator moves 
                 ♦ Suitable for 
                 ♦ Fabrication 
                 ♦ IJ12, IJ13, IJ15, 
               
               
                 chip surface 
                 parallel to the print 
                 planar fabrication 
                 complexity 
                 IJ33, IJ34, IJ35, 
               
               
                   
                 head surface. Drop 
                   
                 ♦ Friction 
                 IJ36 
               
               
                   
                 ejection may still be 
                   
                 ♦ Stiction 
               
               
                   
                 normal to the surface. 
               
               
                 Membrane 
                 An actuator with a 
                 ♦ The effective 
                 ♦ Fabrication 
                 ♦ 1982 Howkins 
               
               
                 push 
                 high force but small 
                 area of the actuator 
                 complexity 
                 USP 4,459,601 
               
               
                   
                 area is used to push a 
                 becomes the 
                 ♦ Actuator size 
               
               
                   
                 stiff membrane that is 
                 membrane area 
                 ♦ Difficulty of 
               
               
                   
                 in contact with the ink. 
                   
                 integration in a 
               
               
                   
                   
                   
                 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 or 
                 increase travel 
                 ♦ May have 
               
               
                   
                 impeller 
                 ♦ Small chip area 
                 friction at a pivot 
               
               
                   
                   
                 requirements 
                 point 
               
               
                 Bend 
                 The actuator bends 
                 ♦ A very small 
                 ♦ Requires the 
                 ♦ 1970 Kyser et al 
               
               
                   
                 when energized. This 
                 change in 
                 actuator to be made 
                 USP 3,946,398 
               
               
                   
                 may be due to 
                 dimensions can be 
                 from at least two 
                 ♦ 1973 Stemme 
               
               
                   
                 differential thermal 
                 converted to a large 
                 distinct layers, or to 
                 USP 3,747,120 
               
               
                   
                 expansion, 
                 motion. 
                 have a thermal 
                 ♦ IJ03, IJ09, IJ10, 
               
               
                   
                 piezoelectric 
                   
                 difference across the 
                 IJ19, IJ23, IJ24, 
               
               
                   
                 expansion, 
                   
                 actuator 
                 IJ25, IJ29, IJ30, 
               
               
                   
                 magnetostriction, or 
                   
                   
                 IJ31, IJ33, IJ34, 
               
               
                   
                 other form of relative 
                   
                   
                 IJ35 
               
               
                   
                 dimensional change. 
               
               
                 Swivel 
                 The actuator swivels 
                 ♦ Allows operation 
                 ♦ Inefficient 
                 ♦ IJ06 
               
               
                   
                 around a central pivot. 
                 where the net linear 
                 coupling to the ink 
               
               
                   
                 This motion is suitable 
                 force on the paddle 
                 motion 
               
               
                   
                 where there are 
                 is zero 
               
               
                   
                 opposite forces 
                 ♦ Small chip area 
               
               
                   
                 applied to opposite 
                 requirements 
               
               
                   
                 sides of the paddle, 
               
               
                   
                 e.g. Lorenz force. 
               
               
                 Straighten 
                 The actuator is 
                 ♦ Can be used with 
                 ♦ Requires careful 
                 ♦ IJ26, IJ32 
               
               
                   
                 normally bent, and 
                 shape memory 
                 balance of stresses 
               
               
                   
                 straightens when 
                 alloys where the 
                 to ensure that the 
               
               
                   
                 energized. 
                 austenic phase is 
                 quiescent bend is 
               
               
                   
                   
                 planar 
                 accurate 
               
               
                 Double 
                 The actuator bends in 
                 ♦ One actuator can 
                 ♦ Difficult to make 
                 ♦ IJ36, IJ37, IJ38 
               
               
                 bend 
                 one direction when 
                 be used to power 
                 the drops ejected by 
               
               
                   
                 one element is 
                 two nozzles. 
                 both bend directions 
               
               
                   
                 energized, and bends 
                 ♦ Reduced chip 
                 identical. 
               
               
                   
                 the other way when 
                 size. 
                 ♦ A small 
               
               
                   
                 another element is 
                 ♦ Not sensitive to 
                 efficiency loss 
               
               
                   
                 energized. 
                 ambient temperature 
                 compared to 
               
               
                   
                   
                   
                 equivalent single 
               
               
                   
                   
                   
                 bend actuators. 
               
               
                 Shear 
                 Energizing the 
                 ♦ Can increase the 
                 ♦ Not readily 
                 ♦ 1985 Fishbeck 
               
               
                   
                 actuator causes a shear 
                 effective travel of 
                 applicable to other 
                 USP 4,584,590 
               
               
                   
                 motion in the actuator 
                 piezoelectric 
                 actuator 
               
               
                   
                 material. 
                 actuators 
                 mechanisms 
               
               
                 Radial con- 
                 The actuator squeezes 
                 ♦ Relatively easy 
                 ♦ High force 
                 ♦ 1970 Zoltan USP 
               
               
                 striction 
                 an ink reservoir, 
                 to fabricate single 
                 required 
                 3,683,212 
               
               
                   
                 forcing ink from a 
                 nozzles from glass 
                 ♦ Inefficient 
               
               
                   
                 constricted nozzle. 
                 tubing as 
                 ♦ Difficult to 
               
               
                   
                   
                 macroscopic 
                 integrate with VLSI 
               
               
                   
                   
                 structures 
                 processes 
               
               
                 Coil/uncoil 
                 A coiled actuator 
                 ♦ Easy to fabricate 
                 ♦ Difficult to 
                 ♦ IJ17, IJ21, IJ34, 
               
               
                   
                 uncoils or coils more 
                 as a planar VLSI 
                 fabricate for non- 
                 IJ35 
               
               
                   
                 tightly. The motion of 
                 process 
                 planar devices 
               
               
                   
                 the free end of the 
                 ♦ Small area 
                 ♦ Poor out-of-plane 
               
               
                   
                 actuator ejects the ink. 
                 required, therefore 
                 stiffness 
               
               
                   
                   
                 low cost 
               
               
                 Bow 
                 The actuator bows (or 
                 ♦ Can increase the 
                 ♦ Maximum travel 
                 ♦ IJ16, IJ18, IJ27 
               
               
                   
                 buckles) in the middle 
                 speed of travel 
                 is constrained 
               
               
                   
                 when energized. 
                 ♦ Mechanically 
                 ♦ High force 
               
               
                   
                   
                 rigid 
                 required 
               
               
                 Push-Pull 
                 Two actuators control 
                 ♦ The structure is 
                 ♦ Not readily 
                 ♦ IJ18 
               
               
                   
                 a shutter. One actuator 
                 pinned at both ends, 
                 suitable for ink jets 
               
               
                   
                 pulls the shutter, and 
                 so has a high out-of- 
                 which directly push 
               
               
                   
                 the other pushes it. 
                 plane rigidity 
                 the ink 
               
               
                 Curl 
                 A set of actuators curl 
                 ♦ Good fluid flow 
                 ♦ Design 
                 ♦ IJ20, IJ42 
               
               
                 inwards 
                 inwards to reduce the 
                 to the region behind 
                 complexity 
               
               
                   
                 volume of ink that 
                 the actuator 
               
               
                   
                 they enclose. 
                 increases efficiency 
               
               
                 Curl 
                 A set of actuators curl 
                 ♦ Relatively simple 
                 ♦ Relatively large 
                 ♦ IJ43 
               
               
                 outwards 
                 outwards, pressurizing 
                 construction 
                 chip area 
               
               
                   
                 ink in a chamber 
               
               
                   
                 surrounding the 
               
               
                   
                 actuators, and 
               
               
                   
                 expelling ink from a 
               
               
                   
                 nozzle in the chamber. 
               
               
                 Iris 
                 Multiple vanes enclose 
                 ♦ High efficiency 
                 ♦ High fabrication 
                 ♦ IJ22 
               
               
                   
                 a volume of ink. These 
                 ♦ Small chip area 
                 complexity 
               
               
                   
                 simultaneously rotate, 
                   
                 ♦ Not suitable for 
               
               
                   
                 reducing the volume 
                   
                 pigmented inks 
               
               
                   
                 between the vanes. 
               
               
                 Acoustic 
                 The actuator vibrates 
                 ♦ The actuator can 
                 ♦ Large area 
                 ♦ 1993 Hadimioglu 
               
               
                 vibration 
                 at a high frequency. 
                 be physically distant 
                 required for 
                 et al, EUP 550,192 
               
               
                   
                   
                 from the ink 
                 efficient operation 
                 ♦ 1993 Elrod et al, 
               
               
                   
                   
                   
                 at useful frequencies 
                 EUP 572,220 
               
               
                   
                   
                   
                 ♦ Acoustic 
               
               
                   
                   
                   
                 coupling and 
               
               
                   
                   
                   
                 crosstalk 
               
               
                   
                   
                   
                 ♦ Complex drive 
               
               
                   
                   
                   
                 circuitry 
               
               
                   
                   
                   
                 ♦ Poor control of 
               
               
                   
                   
                   
                 drop volume and 
               
               
                   
                   
                   
                 position 
               
               
                 None 
                 In various ink jet 
                 ♦ No moving parts 
                 ♦ Various other 
                 ♦ Silverbrook, EP 
               
               
                   
                 designs the actuator 
                   
                 tradeoffs are 
                 0771 658 A2 and 
               
               
                   
                 does not move. 
                   
                 required to 
                 related patent 
               
               
                   
                   
                   
                 eliminate moving 
                 applications 
               
               
                   
                   
                   
                 parts 
                 ♦ Tone-jet 
               
            
           
           
               
            
               
                 NOZZLE REFILL METHOD 
               
            
           
           
               
               
               
               
               
            
               
                 Surface 
                 This is the normal way 
                 ♦ Fabrication 
                 ♦ Low speed 
                 ♦ Thermal ink jet 
               
               
                 tension 
                 that ink jets are 
                 simplicity 
                 ♦ Surface tension 
                 ♦ Piezoelectric ink 
               
               
                   
                 refilled. After the 
                 ♦ Operational 
                 force relatively 
                 jet 
               
               
                   
                 actuator is energized, 
                 simplicity 
                 small compared to 
                 ♦ IJ01-IJ07, IJ10- 
               
               
                   
                 it typically returns 
                   
                 actuator force 
                 IJ14, IJ16, IJ20, 
               
               
                   
                 rapidly to its normal 
                   
                 ♦ Long refill time 
                 IJ22-IJ45 
               
               
                   
                 position. This rapid 
                   
                 usually dominates 
               
               
                   
                 return sucks in air 
                   
                 the total repetition 
               
               
                   
                 through the nozzle 
                   
                 rate 
               
               
                   
                 opening. The ink 
               
               
                   
                 surface tension at the 
               
               
                   
                 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 at 
                 ♦ Low actuator 
                 common ink 
                 IJ17, IJ18, IJ19, 
               
               
                 ink pressure 
                 a pressure that 
                 energy, as the 
                 pressure oscillator 
                 IJ21 
               
               
                   
                 oscillates at twice the 
                 actuator need only 
                 ♦ May not be 
               
               
                   
                 drop ejection 
                 open or close the 
                 suitable for 
               
               
                   
                 frequency. When a 
                 shutter, instead of 
                 pigmented inks 
               
               
                   
                 drop is to be ejected, 
                 ejecting the ink drop 
               
               
                   
                 the shutter is opened 
               
               
                   
                 for 3 half cycles: drop 
               
               
                   
                 ejection, actuator 
               
               
                   
                 return, and refill. The 
               
               
                   
                 shutter is then closed 
               
               
                   
                 to prevent the nozzle 
               
               
                   
                 chamber emptying 
               
               
                   
                 during the next 
               
               
                   
                 negative pressure 
               
               
                   
                 cycle. 
               
               
                 Refill 
                 After the main 
                 ♦ High speed, as 
                 ♦ Requires two 
                 ♦ IJ09 
               
               
                 actuator 
                 actuator has ejected a 
                 the nozzle is 
                 independent 
               
               
                   
                 drop a second (refill) 
                 actively refilled 
                 actuators per nozzle 
               
               
                   
                 actuator is energized. 
               
               
                   
                 The refill actuator 
               
               
                   
                 pushes ink into the 
               
               
                   
                 nozzle chamber. The 
               
               
                   
                 refill actuator returns 
               
               
                   
                 slowly, to prevent its 
               
               
                   
                 return from emptying 
               
               
                   
                 the chamber again. 
               
               
                 Positive ink 
                 The ink is held a slight 
                 ♦ High refill rate, 
                 ♦ Surface spill 
                 ♦ Silverbrook, EP 
               
               
                 pressure 
                 positive pressure. 
                 therefore a high 
                 must be prevented 
                 0771 658 A2 and 
               
               
                   
                 After the ink drop is 
                 drop repetition rate 
                 ♦ Highly 
                 related patent 
               
               
                   
                 ejected, the nozzle 
                 is possible 
                 hydrophobic print 
                 applications 
               
               
                   
                 chamber fills quickly 
                   
                 head surfaces are 
                 ♦ Alternative for:, 
               
               
                   
                 as surface tension and 
                   
                 required 
                 IJ01-IJ07, IJ10-IJ14, 
               
               
                   
                 ink pressure both 
                   
                   
                 IJ16, IJ20, IJ22-IJ45 
               
               
                   
                 operate to refill the 
               
               
                   
                 nozzle. 
               
            
           
           
               
            
               
                 METHOD OF RESTRICTING BACK-FLOW THROUGH INLET 
               
            
           
           
               
               
               
               
               
            
               
                 Long inlet 
                 The ink inlet channel 
                 ♦ Design simplicity 
                 ♦ Restricts refill 
                 ♦ Thermal ink jet 
               
               
                 channel 
                 to the nozzle chamber 
                 ♦ Operational 
                 rate 
                 ♦ Piezoelectric ink 
               
               
                   
                 is made long and 
                 simplicity 
                 ♦ May result in a 
                 jet 
               
               
                   
                 relatively narrow, 
                 ♦ Reduces 
                 relatively large chip 
                 ♦ IJ42, IJ43 
               
               
                   
                 relying on viscous 
                 crosstalk 
                 area 
               
               
                   
                 drag to reduce inlet 
                   
                 ♦ Only partially 
               
               
                   
                 back-flow. 
                   
                 effective 
               
               
                 Positive ink 
                 The ink is under a 
                 ♦ Drop selection 
                 ♦ Requires a 
                 ♦ Silverbrook, EP 
               
               
                 pressure 
                 positive pressure, so 
                 and separation 
                 method (such as a 
                 0771 658 A2 and 
               
               
                   
                 that in the quiescent 
                 forces can be 
                 nozzle rim or 
                 related patent 
               
               
                   
                 state some of the ink 
                 reduced 
                 effective 
                 applications 
               
               
                   
                 drop already protrudes 
                 ♦ Fast refill time 
                 hydrophobizing, or 
                 ♦ Possible 
               
               
                   
                 from the nozzle. 
                   
                 both) to prevent 
                 operation of the 
               
               
                   
                 This reduces the 
                   
                 flooding of the 
                 following: IJ01- 
               
               
                   
                 pressure in the nozzle 
                   
                 ejection surface of 
                 IJ07, IJ09-IJ12, 
               
               
                   
                 chamber which is 
                   
                 the print head. 
                 IJ14, IJ16, IJ20, 
               
               
                   
                 required to eject a 
                   
                   
                 IJ22, IJ23-IJ34, 
               
               
                   
                 certain volume of ink. 
                   
                   
                 IJ36-IJ41, IJ44 
               
               
                   
                 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 
               
               
                   
                 are placed in the inlet 
                 not as restricted as 
                 complexity 
                 Jet 
               
               
                   
                 ink flow. When the 
                 the long inlet 
                 ♦ May increase 
                 ♦ Tektronix 
               
               
                   
                 actuator is energized, 
                 method. 
                 fabrication 
                 piezoelectric ink jet 
               
               
                   
                 the rapid ink 
                 ♦ Reduces 
                 complexity (e.g. 
               
               
                   
                 movement creates 
                 crosstalk 
                 Tektronix hot melt 
               
               
                   
                 eddies which restrict 
                   
                 Piezoelectric print 
               
               
                   
                 the flow through the 
                   
                 heads). 
               
               
                   
                 inlet. The slower refill 
               
               
                   
                 process is unrestricted, 
               
               
                   
                 and does not result in 
               
               
                   
                 eddies. 
               
               
                 Flexible flap 
                 In this method recently 
                 ♦ Significantly 
                 ♦ Not applicable to 
                 ♦ Canon 
               
               
                 restricts 
                 disclosed by Canon, 
                 reduces back-flow 
                 most ink jet 
               
               
                 inlet 
                 the expanding actuator 
                 for edge-shooter 
                 configurations 
               
               
                   
                 (bubble) pushes on a 
                 thermal ink jet 
                 ♦ Increased 
               
               
                   
                 flexible flap that 
                 devices 
                 fabrication 
               
               
                   
                 restricts the inlet. 
                   
                 complexity 
               
               
                   
                   
                   
                 ♦ 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 ink 
                 rate 
                 IJ27, IJ29, IJ30 
               
               
                   
                 and the nozzle 
                 filtration 
                 ♦ May result in 
               
               
                   
                 chamber. The filter 
                 ♦ Ink filter may be 
                 complex 
               
               
                   
                 has a multitude of 
                 fabricated with no 
                 construction 
               
               
                   
                 small holes or slots, 
                 additional process 
               
               
                   
                 restricting ink flow. 
                 steps 
               
               
                   
                 The filter also removes 
               
               
                   
                 particles which may 
               
               
                   
                 block the nozzle. 
               
               
                 Small inlet 
                 The ink inlet channel 
                 ♦ Design simplicity 
                 ♦ Restricts refill 
                 ♦ IJ02, IJ37, IJ44 
               
               
                 compared 
                 to the nozzle chamber 
                   
                 rate 
               
               
                 to nozzle 
                 has a substantially 
                   
                 ♦ May result in a 
               
               
                   
                 smaller cross section 
                   
                 relatively large chip 
               
               
                   
                 than that of the nozzle, 
                   
                 area 
               
               
                   
                 resulting in easier ink 
                   
                 ♦ Only partially 
               
               
                   
                 egress out of the 
                   
                 effective 
               
               
                   
                 nozzle than out of the 
               
               
                   
                 inlet. 
               
               
                 Inlet shutter 
                 A secondary actuator 
                 ♦ Increases speed 
                 ♦ Requires separate 
                 ♦ IJ09 
               
               
                   
                 controls the position of 
                 of the ink-jet print 
                 refill actuator and 
               
               
                   
                 a shutter, closing off 
                 head operation 
                 drive circuit 
               
               
                   
                 the ink inlet when the 
               
               
                   
                 main actuator is 
               
               
                   
                 energized. 
               
               
                 The inlet is 
                 The method avoids the 
                 ♦ Back-flow 
                 ♦ Requires careful 
                 ♦ IJ01, IJ03, IJ05, 
               
               
                 located 
                 problem of inlet back- 
                 problem is 
                 design to minimize 
                 IJ06, IJ07, IJ10, 
               
               
                 behind the 
                 flow by arranging the 
                 eliminated 
                 the negative 
                 IJ11, IJ14, IJ16, 
               
               
                 ink-pushing 
                 ink-pushing surface of 
                   
                 pressure behind the 
                 IJ22, IJ23, IJ25, 
               
               
                 surface 
                 the actuator between 
                   
                 paddle 
                 IJ28, IJ31, IJ32, 
               
               
                   
                 the inlet and the 
                   
                   
                 IJ33, IJ34, IJ35, 
               
               
                   
                 nozzle. 
                   
                   
                 IJ36, IJ39, IJ40, 
               
               
                   
                   
                   
                   
                 IJ41 
               
               
                 Part of the 
                 The actuator and a 
                 ♦ Significant 
                 ♦ Small increase in 
                 ♦ IJ07, IJ20, IJ26, 
               
               
                 actuator 
                 wall of the ink 
                 reductions in back- 
                 fabrication 
                 IJ38 
               
               
                 moves to 
                 chamber are arranged 
                 flow can be 
                 complexity 
               
               
                 shut off the 
                 so that the motion of 
                 achieved 
               
               
                 inlet 
                 the actuator closes off 
                 ♦ Compact designs 
               
               
                   
                 the inlet. 
                 possible 
               
               
                 Nozzle 
                 In some configurations 
                 ♦ Ink back-flow 
                 ♦ None related to 
                 ♦ Silverbrook, EP 
               
               
                 actuator 
                 of ink jet, there is no 
                 problem is 
                 ink back-flow on 
                 0771 658 A2 and 
               
               
                 does not 
                 expansion or 
                 eliminated 
                 actuation 
                 related patent 
               
               
                 result in ink 
                 movement of an 
                   
                   
                 applications 
               
               
                 back-flow 
                 actuator which may 
                   
                   
                 ♦ Valve-jet 
               
               
                   
                 cause ink back-flow 
                   
                   
                 ♦ Tone-jet 
               
               
                   
                 through the inlet. 
               
            
           
           
               
            
               
                 NOZZLE CLEARING METHOD 
               
            
           
           
               
               
               
               
               
            
               
                 Normal 
                 All of the nozzles are 
                 ♦ No added 
                 ♦ May not be 
                 ♦ Most ink jet 
               
               
                 nozzle firing 
                 fired periodically, 
                 complexity on the 
                 sufficient to 
                 systems 
               
               
                   
                 before the ink has a 
                 print head 
                 displace dried ink 
                 ♦ IJ01, IJ02, IJ03, 
               
               
                   
                 chance to dry. When 
                   
                   
                 IJ04, IJ05, IJ06, 
               
               
                   
                 not in use the nozzles 
                   
                   
                 IJ07, IJ09, IJ10, 
               
               
                   
                 are sealed (capped) 
                   
                   
                 IJ11, IJ12, IJ14, 
               
               
                   
                 against air. 
                   
                   
                 IJ16, IJ20, IJ22, 
               
               
                   
                 The nozzle firing is 
                   
                   
                 IJ23, IJ24, IJ25, 
               
               
                   
                 usually performed 
                   
                   
                 IJ26, IJ27, IJ28, 
               
               
                   
                 during a special 
                   
                   
                 IJ29, IJ30, IJ31, 
               
               
                   
                 clearing cycle, after 
                   
                   
                 IJ32, IJ33, IJ34, 
               
               
                   
                 first moving the print 
                   
                   
                 IJ36, IJ37, IJ38, 
               
               
                   
                 head to a cleaning 
                   
                   
                 IJ39, IJ40, IJ41, 
               
               
                   
                 station. 
                   
                   
                 IJ42, IJ43, IJ44, 
               
               
                   
                   
                   
                   
                 IJ45 
               
               
                 Extra 
                 In systems which heat 
                 ♦ Can be highly 
                 ♦ Requires higher 
                 ♦ Silverbrook, EP 
               
               
                 power to 
                 the ink, but do not boil 
                 effective if the 
                 drive voltage for 
                 0771 658 A2 and 
               
               
                 ink heater 
                 it under normal 
                 heater is adjacent to 
                 clearing 
                 related patent 
               
               
                   
                 situations, nozzle 
                 the nozzle 
                 ♦ May require 
                 applications 
               
               
                   
                 clearing can be 
                   
                 larger drive 
               
               
                   
                 achieved by over- 
                   
                 transistors 
               
               
                   
                 powering the heater 
               
               
                   
                 and boiling ink at the 
               
               
                   
                 nozzle. 
               
               
                 Rapid 
                 The actuator is fired in 
                 ♦ Does not require 
                 ♦ Effectiveness 
                 ♦ May be used 
               
               
                 success-ion 
                 rapid succession. In 
                 extra drive circuits 
                 depends 
                 with: IJ01, IJ02, 
               
               
                 of actuator 
                 some configurations, 
                 on the print head 
                 substantially upon 
                 IJ03, IJ04, IJ05, 
               
               
                 pulses 
                 this may cause heat 
                 ♦ Can be readily 
                 the configuration of 
                 IJ06, IJ07, IJ09, 
               
               
                   
                 build-up at the nozzle 
                 controlled and 
                 the ink jet nozzle 
                 IJ10, IJ11, IJ14, 
               
               
                   
                 which boils the ink, 
                 initiated by digital 
                   
                 IJ16, IJ20, IJ22, 
               
               
                   
                 clearing the nozzle. In 
                 logic 
                   
                 IJ23, IJ24, IJ25, 
               
               
                   
                 other situations, it may 
                   
                   
                 IJ27, IJ28, IJ29, 
               
               
                   
                 cause sufficient 
                   
                   
                 IJ30, IJ31, IJ32, 
               
               
                   
                 vibrations to dislodge 
                   
                   
                 IJ33, IJ34, IJ36, 
               
               
                   
                 clogged nozzles. 
                   
                   
                 IJ37, IJ38, IJ39, 
               
               
                   
                   
                   
                   
                 IJ40, IJ41, IJ42, 
               
               
                   
                   
                   
                   
                 IJ43, IJ44, IJ45 
               
               
                 Extra 
                 Where an actuator is 
                 ♦ A simple 
                 ♦ Not suitable 
                 ♦ May be used 
               
               
                 power to 
                 not normally driven to 
                 solution where 
                 where there is a 
                 with: IJ03, IJ09, 
               
               
                 ink pushing 
                 the limit of its motion, 
                 applicable 
                 hard limit to 
                 IJ16, IJ20, IJ23, 
               
               
                 actuator 
                 nozzle clearing may be 
                   
                 actuator movement 
                 IJ24, IJ25, IJ27, 
               
               
                   
                 assisted by providing 
                   
                   
                 IJ29, IJ30, IJ31, 
               
               
                   
                 an enhanced drive 
                   
                   
                 IJ32, IJ39, IJ40, 
               
               
                   
                 signal to the actuator. 
                   
                   
                 IJ41, IJ42, IJ43, 
               
               
                   
                   
                   
                   
                 IJ44, IJ45 
               
               
                 Acoustic 
                 An ultrasonic wave is 
                 ♦ A high nozzle 
                 ♦ High 
                 ♦ IJ08, IJ13, IJ15, 
               
               
                 resonance 
                 applied to the ink 
                 clearing capability 
                 implementation cost 
                 IJ17, IJ18, IJ19, 
               
               
                   
                 chamber. This wave is 
                 can be achieved 
                 if system does not 
                 IJ21 
               
               
                   
                 of an appropriate 
                 ♦ May be 
                 already include an 
               
               
                   
                 amplitude and 
                 implemented at very 
                 acoustic actuator 
               
               
                   
                 frequency to cause 
                 low cost in systems 
               
               
                   
                 sufficient force at the 
                 which already 
               
               
                   
                 nozzle to clear 
                 include acoustic 
               
               
                   
                 blockages. This is 
                 actuators 
               
               
                   
                 easiest to achieve if 
               
               
                   
                 the ultrasonic wave is 
               
               
                   
                 at a resonant 
               
               
                   
                 frequency of the ink 
               
               
                   
                 cavity. 
               
               
                 Nozzle 
                 A microfabricated 
                 ♦ Can clear 
                 ♦ Accurate 
                 ♦ Silverbrook, EP 
               
               
                 clearing 
                 plate is pushed against 
                 severely clogged 
                 mechanical 
                 0771 658 A2 and 
               
               
                 plate 
                 the nozzles. The plate 
                 nozzles 
                 alignment is 
                 related patent 
               
               
                   
                 has a post for every 
                   
                 required 
                 applications 
               
               
                   
                 nozzle. A post moves 
                   
                 ♦ Moving parts are 
               
               
                   
                 through each nozzle, 
                   
                 required 
               
               
                   
                 displacing dried ink. 
                   
                 ♦ There is risk of 
               
               
                   
                   
                   
                 damage to the 
               
               
                   
                   
                   
                 nozzles 
               
               
                   
                   
                   
                 ♦ Accurate 
               
               
                   
                   
                   
                 fabrication is 
               
               
                   
                   
                   
                 required 
               
               
                 Ink 
                 The pressure of the ink 
                 ♦ May be effective 
                 ♦ Requires 
                 ♦ May be used 
               
               
                 pressure 
                 is temporarily 
                 where other 
                 pressure pump or 
                 with all IJ series ink 
               
               
                 pulse 
                 increased so that ink 
                 methods cannot be 
                 other pressure 
                 jets 
               
               
                   
                 streams from all of the 
                 used 
                 actuator 
               
               
                   
                 nozzles. This may be 
                   
                 ♦ Expensive 
               
               
                   
                 used in conjunction 
                   
                 ♦ Wasteful of ink 
               
               
                   
                 with actuator 
               
               
                   
                 energizing. 
               
               
                 Print head 
                 A flexible ‘blade’ is 
                 ♦ Effective for 
                 ♦ Difficult to use if 
                 ♦ Many ink jet 
               
               
                 wiper 
                 wiped across the print 
                 planar print head 
                 print head surface is 
                 systems 
               
               
                   
                 head surface. The 
                 surfaces 
                 non-planar or very 
               
               
                   
                 blade is usually 
                 ♦ Low cost 
                 fragile 
               
               
                   
                 fabricated from a 
                   
                 ♦ Requires 
               
               
                   
                 flexible polymer, e.g. 
                   
                 mechanical parts 
               
               
                   
                 rubber or synthetic 
                   
                 ♦ Blade can wear 
               
               
                   
                 elastomer. 
                   
                 out in high volume 
               
               
                   
                   
                   
                 print systems 
               
               
                 Separate 
                 A separate heater is 
                 ♦ Can be effective 
                 ♦ Fabrication 
                 ♦ Can be used with 
               
               
                 ink boiling 
                 provided at the nozzle 
                 where other nozzle 
                 complexity 
                 many IJ series ink 
               
               
                 heater 
                 although the normal 
                 clearing methods 
                   
                 jets 
               
               
                   
                 drop e-ection 
                 cannot be used 
               
               
                   
                 mechanism does not 
                 ♦ Can be 
               
               
                   
                 require it. The heaters 
                 implemented at no 
               
               
                   
                 do not require 
                 additional cost in 
               
               
                   
                 individual drive 
                 some ink jet 
               
               
                   
                 circuits, as many 
                 configurations 
               
               
                   
                 nozzles can be cleared 
               
               
                   
                 simultaneously, and no 
               
               
                   
                 imaging is required. 
               
            
           
           
               
            
               
                 NOZZLE PLATE CONSTRUCTION 
               
            
           
           
               
               
               
               
               
            
               
                 Electro- 
                 A nozzle plate is 
                 ♦ Fabrication 
                 ♦ High 
                 ♦ Hewlett Packard 
               
               
                 formed 
                 separately fabricated 
                 simplicity. 
                 temperatures and 
                 Thermal Ink jet 
               
               
                 nickel 
                 from electroformed 
                   
                 pressures are 
               
               
                   
                 nickel, and bonded to 
                   
                 required to bond 
               
               
                   
                 the print head chip. 
                   
                 nozzle plate 
               
               
                   
                   
                   
                 ♦ Minimum 
               
               
                   
                   
                   
                 thickness constraints 
               
               
                   
                   
                   
                 ♦ Differential 
               
               
                   
                   
                   
                 thermal expansion 
               
               
                 Laser 
                 Individual nozzle 
                 ♦ No masks 
                 ♦ Each hole must 
                 ♦ Canon Bubblejet 
               
               
                 ablated or 
                 holes are ablated by an 
                 required 
                 be individually 
                 ♦ 1988 Sercel et 
               
               
                 drilled 
                 intense UV laser in a 
                 ♦ Can be quite fast 
                 formed 
                 al., SPIE, Vol. 998 
               
               
                 polymer 
                 nozzle plate, which is 
                 ♦ Some control 
                 ♦ Special 
                 Excimer Beam 
               
               
                   
                 typically a polymer 
                 over nozzle profile 
                 equipment required 
                 Applications, pp. 
               
               
                   
                 such as polyimide or 
                 is possible 
                 ♦ Slow where there 
                 76-83 
               
               
                   
                 polysulphone 
                 ♦ Equipment 
                 are many thousands 
                 ♦ 1993 Watanabe 
               
               
                   
                   
                 required is relatively 
                 of nozzles per print 
                 et al., USP 
               
               
                   
                   
                 low cost 
                 head 
                 5,208,604 
               
               
                   
                   
                   
                 ♦ May produce thin 
               
               
                   
                   
                   
                 burrs at exit holes 
               
               
                 Silicon 
                 A separate nozzle 
                 ♦ High accuracy is 
                 ♦ Two part 
                 ♦ K. Bean, IEEE 
               
               
                 micro- 
                 plate is 
                 attainable 
                 construction 
                 Transactions on 
               
               
                 machined 
                 micromachined from 
                   
                 ♦ High cost 
                 Electron Devices, 
               
               
                   
                 single crystal silicon, 
                   
                 ♦ Requires 
                 Vol. ED-25, No. 10, 
               
               
                   
                 and bonded to the 
                   
                 precision alignment 
                 1978, pp 1185-1195 
               
               
                   
                 print head wafer. 
                   
                 ♦ Nozzles may be 
                 ♦ Xerox 1990 
               
               
                   
                   
                   
                 clogged by adhesive 
                 Hawkins et al., USP 
               
               
                   
                   
                   
                   
                 4,899,181 
               
               
                 Glass 
                 Fine glass capillaries 
                 ♦ No expensive 
                 ♦ Very small 
                 ♦ 1970 Zoltan USP 
               
               
                 capillaries 
                 are drawn from glass 
                 equipment required 
                 nozzle sizes are 
                 3,683,212 
               
               
                   
                 tubing. This method 
                 ♦ Simple to make 
                 difficult to form 
               
               
                   
                 has been used for 
                 single nozzles 
                 ♦ Not suited for 
               
               
                   
                 making individual 
                   
                 mass production 
               
               
                   
                 nozzles, but is difficult 
               
               
                   
                 to use for bulk 
               
               
                   
                 manufacturing of print 
               
               
                   
                 heads with thousands 
               
               
                   
                 of nozzles. 
               
               
                 Monolithic, 
                 The nozzle plate is 
                 ♦ High accuracy 
                 ♦ Requires 
                 ♦ Silverbrook, EP 
               
               
                 surface 
                 deposited as a layer 
                 (&lt;1 μm) 
                 sacrificial layer 
                 0771 658 A2 and 
               
               
                 micro- 
                 using standard VLSI 
                 ♦ Monolithic 
                 under the nozzle 
                 related patent 
               
               
                 machined 
                 deposition techniques. 
                 ♦ Low cost 
                 plate to form the 
                 applications 
               
               
                 using VLSI 
                 Nozzles are etched in 
                 ♦ Existing 
                 nozzle chamber 
                 ♦ IJ01, IJ02, IJ04, 
               
               
                 litho- 
                 the nozzle plate using 
                 processes can be 
                 ♦ Surface may be 
                 IJ11, IJ12, IJ17, 
               
               
                 graphic 
                 VLSI lithography and 
                 used 
                 fragile to the touch 
                 IJ18, IJ20, IJ22, 
               
               
                 processes 
                 etching. 
                   
                   
                 IJ24, IJ27, IJ28, 
               
               
                   
                   
                   
                   
                 IJ29, IJ30, IJ31, 
               
               
                   
                   
                   
                   
                 IJ32, IJ33, IJ34, 
               
               
                   
                   
                   
                   
                 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 the 
                 (&lt;1 μm) 
                 etch times 
                 IJ07, IJ08, IJ09, 
               
               
                 through 
                 wafer. Nozzle 
                 ♦ Monolithic 
                 ♦ Requires a 
                 IJ10, IJ13, IJ14, 
               
               
                 substrate 
                 chambers are etched in 
                 ♦ Low cost 
                 support wafer 
                 IJ15, IJ16, IJ19, 
               
               
                   
                 the front of the wafer, 
                 ♦ No differential 
                   
                 IJ21, IJ23, IJ25, 
               
               
                   
                 and the wafer is 
                 expansion 
                   
                 IJ26 
               
               
                   
                 thinned from the back 
               
               
                   
                 side. Nozzles are then 
               
               
                   
                 etched in the etch stop 
               
               
                   
                 layer. 
               
               
                 No nozzle 
                 Various methods have 
                 ♦ No nozzles to 
                 ♦ Difficult to 
                 ♦ Ricoh 1995 
               
               
                 plate 
                 been tried to eliminate 
                 become clogged 
                 control drop 
                 Sekiya et al USP 
               
               
                   
                 the nozzles entirely, to 
                   
                 position accurately 
                 5,412,413 
               
               
                   
                 prevent nozzle 
                   
                 ♦ Crosstalk 
                 ♦ 1993 Hadimioglu 
               
               
                   
                 clogging. These 
                   
                 problems 
                 et al EUP 550,192 
               
               
                   
                 include thermal bubble 
                   
                   
                 ♦ 1993 Elrod et al 
               
               
                   
                 mechanisms and 
                   
                   
                 EUP 572,220 
               
               
                   
                 acoustic lens 
               
               
                   
                 mechanisms 
               
               
                 Trough 
                 Each drop ejector has 
                 ♦ Reduced 
                 ♦ Drop firing 
                 ♦ IJ35 
               
               
                   
                 a trough through 
                 manufacturing 
                 direction is sensitive 
               
               
                   
                 which a paddle moves. 
                 complexity 
                 to wicking. 
               
               
                   
                 There is no nozzle 
                 ♦ Monolithic 
               
               
                   
                 plate. 
               
               
                 Nozzle slit 
                 The elimination of 
                 ♦ No nozzles to 
                 ♦ Difficult to 
                 ♦ 1989 Saito et al 
               
               
                 instead of 
                 nozzle holes and 
                 become clogged 
                 control drop 
                 USP 4,799,068 
               
               
                 individual 
                 replacement by a slit 
                   
                 position accurately 
               
               
                 nozzles 
                 encompassing many 
                   
                 ♦ Crosstalk 
               
               
                   
                 actuator positions 
                   
                 problems 
               
               
                   
                 reduces nozzle 
               
               
                   
                 clogging, but increases 
               
               
                   
                 crosstalk due to ink 
               
               
                   
                 surface waves 
               
            
           
           
               
            
               
                 DROP EJECTION DIRECTION 
               
            
           
           
               
               
               
               
               
            
               
                 Edge 
                 Ink flow is along the 
                 ♦ Simple 
                 ♦ Nozzles limited 
                 ♦ Canon Bubblejet 
               
               
                 (‘edge 
                 surface of the chip, 
                 construction 
                 to edge 
                 1979 Endo et al GB 
               
               
                 shooter’) 
                 and ink drops are 
                 ♦ No silicon 
                 ♦ High resolution 
                 patent 2,007,162 
               
               
                   
                 ejected from the chip 
                 etching required 
                 is difficult 
                 ♦ Xerox heater-in- 
               
               
                   
                 edge. 
                 ♦ Good heat 
                 ♦ Fast color 
                 pit 1990 Hawkins et 
               
               
                   
                   
                 sinking via substrate 
                 printing requires 
                 al USP 4,899,181 
               
               
                   
                   
                 ♦ Mechanically 
                 one print head per 
                 ♦ Tone-jet 
               
               
                   
                   
                 strong 
                 color 
               
               
                   
                   
                 ♦ Ease of chip 
               
               
                   
                   
                 handing 
               
               
                 Surface 
                 Ink flow is along the 
                 ♦ No bulk silicon 
                 ♦ Maximum ink 
                 ♦ Hewlett-Packard 
               
               
                 (‘roof 
                 surface of the chip, 
                 etching required 
                 flow is severely 
                 TIJ 1982 Vaught et 
               
               
                 shooter’) 
                 and ink drops are 
                 ♦ Silicon can make 
                 restricted 
                 al USP 4,490,728 
               
               
                   
                 ejected from the chip 
                 an effective heat 
                   
                 ♦ IJ02, IJ11, IJ12, 
               
               
                   
                 surface, normal to the 
                 sink 
                   
                 IJ20, IJ22 
               
               
                   
                 plane of the chip. 
                 ♦ Mechanical 
               
               
                   
                   
                 strength 
               
               
                 Through 
                 Ink flow is through the 
                 ♦ High ink flow 
                 ♦ Requires bulk 
                 ♦ Silverbrook, EP 
               
               
                 chip, 
                 chip, and ink drops are 
                 ♦ Suitable for 
                 silicon etching 
                 0771 658 A2 and 
               
               
                 forward 
                 ejected from the front 
                 pagewidth print 
                   
                 related patent 
               
               
                 (‘up 
                 surface of the chip. 
                 heads 
                   
                 applications 
               
               
                 shooter’) 
                   
                 ♦ High nozzle 
                   
                 ♦ IJ04, IJ17, IJ18, 
               
               
                   
                   
                 packing density 
                   
                 IJ24, IJ27-IJ45 
               
               
                   
                   
                 therefore low 
               
               
                   
                   
                 manufacturing cost 
               
               
                 Through 
                 Ink flow is through the 
                 ♦ High ink flow 
                 ♦ Requires wafer 
                 ♦ IJ01, IJ03, IJ05, 
               
               
                 chip, 
                 chip, and ink drops are 
                 ♦ Suitable for 
                 thinning 
                 IJ06, IJ07, IJ08, 
               
               
                 reverse 
                 ejected from the rear 
                 pagewidth print 
                 ♦ Requires special 
                 IJ09, IJ10, IJ13, 
               
               
                 (‘down 
                 surface of the chip. 
                 heads 
                 handling during 
                 IJ14, IJ15, IJ16, 
               
               
                 shooter’) 
                   
                 ♦ High nozzle 
                 manufacture 
                 IJ19, IJ21, IJ23, 
               
               
                   
                   
                 packing density 
                   
                 IJ25, IJ26 
               
               
                   
                   
                 therefore low 
               
               
                   
                   
                 manufacturing cost 
               
               
                 Through 
                 Ink flow is through the 
                 ♦ Suitable for 
                 ♦ Pagewidth print 
                 ♦ Epson Stylus 
               
               
                 actuator 
                 actuator, which is not 
                 piezoelectric print 
                 heads require 
                 ♦ Tektronix hot 
               
               
                   
                 fabricated as part of 
                 heads 
                 several thousand 
                 melt piezoelectric 
               
               
                   
                 the same substrate as 
                   
                 connections to drive 
                 ink jets 
               
               
                   
                 the drive transistors. 
                   
                 circuits 
               
               
                   
                   
                   
                 ♦ Cannot be 
               
               
                   
                   
                   
                 manufactured in 
               
               
                   
                   
                   
                 standard CMOS 
               
               
                   
                   
                   
                 fabs 
               
               
                   
                   
                   
                 ♦ Complex 
               
               
                   
                   
                   
                 assembly required 
               
            
           
           
               
            
               
                 INK TYPE 
               
            
           
           
               
               
               
               
               
            
               
                 Aqueous, 
                 Water based ink which 
                 ♦ Environmentally 
                 ♦ Slow drying 
                 ♦ Most existing ink 
               
               
                 dye 
                 typically contains: 
                 friendly 
                 ♦ Corrosive 
                 jets 
               
               
                   
                 water, dye, surfactant, 
                 ♦ No odor 
                 ♦ Bleeds on paper 
                 ♦ All IJ series ink 
               
               
                   
                 humectant, and 
                   
                 ♦ May 
                 jets 
               
               
                   
                 biocide. 
                   
                 strikethrough 
                 ♦ Silverbrook, EP 
               
               
                   
                 Modern ink dyes have 
                   
                 ♦ Cockles paper 
                 0771 658 A2 and 
               
               
                   
                 high water-fastness, 
                   
                   
                 related patent 
               
               
                   
                 light fastness 
                   
                   
                 applications 
               
               
                 Aqueous, 
                 Water based ink which 
                 ♦ Environmentally 
                 ♦ Slow drying 
                 ♦ IJ02, IJ04, IJ21, 
               
               
                 pigment 
                 typically contains: 
                 friendly 
                 ♦ Corrosive 
                 IJ26, IJ27, IJ30 
               
               
                   
                 water, pigment, 
                 ♦ No odor 
                 ♦ Pigment may 
                 ♦ Silverbrook, EP 
               
               
                   
                 surfactant, humectant, 
                 ♦ Reduced bleed 
                 clog nozzles 
                 0771 658 A2 and 
               
               
                   
                 and biocide. 
                 ♦ Reduced wicking 
                 ♦ Pigment may 
                 related patent 
               
               
                   
                 Pigments have an 
                 ♦ Reduced 
                 clog actuator 
                 applications 
               
               
                   
                 advantage in reduced 
                 strikethrough 
                 mechanisms 
                 ♦ Piezoelectric ink- 
               
               
                   
                 bleed, wicking and 
                   
                 ♦ Cockles paper 
                 jets 
               
               
                   
                 strikethrough. 
                   
                   
                 ♦ Thermal ink jets 
               
               
                   
                   
                   
                   
                 (with significant 
               
               
                   
                   
                   
                   
                 restrictions) 
               
               
                 Methyl 
                 MEK is a highly 
                 ♦ Very fast drying 
                 ♦ Odorous 
                 ♦ All IJ series ink 
               
               
                 Ethyl 
                 volatile solvent used 
                 ♦ Prints on various 
                 ♦ Flammable 
                 jets 
               
               
                 Ketone 
                 for industrial printing 
                 substrates such as 
               
               
                 (MEK) 
                 on difficult surfaces 
                 metals and plastics 
               
               
                   
                 such as aluminum 
               
               
                   
                 cans. 
               
               
                 Alcohol 
                 Alcohol based inks 
                 ♦ Fast drying 
                 ♦ Slight odor 
                 ♦ All IJ series ink 
               
               
                 (ethanol, 2- 
                 can be used where the 
                 ♦ Operates at sub- 
                 ♦ Flammable 
                 jets 
               
               
                 butanol, 
                 printer must operate at 
                 freezing 
               
               
                 and others) 
                 temperatures below 
                 temperatures 
               
               
                   
                 the freezing point of 
                 ♦ Reduced paper 
               
               
                   
                 water. An example of 
                 cockle 
               
               
                   
                 this is in-camera 
                 ♦ Low cost 
               
               
                   
                 consumer 
               
               
                   
                 photographic printing. 
               
               
                 Phase 
                 The ink is solid at 
                 ♦ No drying time- 
                 ♦ High viscosity 
                 ♦ Tektronix hot 
               
               
                 change 
                 room temperature, and 
                 ink instantly freezes 
                 ♦ Printed ink 
                 melt piezoelectric 
               
               
                 (hot melt) 
                 is melted in the print 
                 on the print medium 
                 typically has a 
                 ink jets 
               
               
                   
                 head before jetting. 
                 ♦ Almost any print 
                 ‘waxy’ feel 
                 ♦ 1989 Nowak 
               
               
                   
                 Hot melt inks are 
                 medium can be used 
                 ♦ Printed pages 
                 USP 4,820,346 
               
               
                   
                 usually wax based, 
                 ♦ No paper cockle 
                 may ‘block’ 
                 ♦ All IJ series ink 
               
               
                   
                 with a melting point 
                 occurs 
                 ♦ Ink temperature 
                 jets 
               
               
                   
                 around 80° C. After 
                 ♦ No wicking 
                 may be above the 
               
               
                   
                 jetting the ink freezes 
                 occurs 
                 curie point of 
               
               
                   
                 almost instantly upon 
                 ♦ No bleed occurs 
                 permanent magnets 
               
               
                   
                 contacting the print 
                 ♦ No strikethrough 
                 ♦ Ink heaters 
               
               
                   
                 medium or a transfer 
                 occurs 
                 consume power 
               
               
                   
                 roller. 
                   
                 ♦ Long warm-up 
               
               
                   
                   
                   
                 time 
               
               
                 Oil 
                 Oil based inks are 
                 ♦ High solubility 
                 ♦ High viscosity: 
                 ♦ All IJ series ink 
               
               
                   
                 extensively used in 
                 medium for some 
                 this is a significant 
                 jets 
               
               
                   
                 offset printing. They 
                 dyes 
                 limitation for use in 
               
               
                   
                 have advantages in 
                 ♦ Does not cockle 
                 ink jets, which 
               
               
                   
                 improved 
                 paper 
                 usually require a 
               
               
                   
                 characteristics on 
                 ♦ Does not wick 
                 low viscosity. Some 
               
               
                   
                 paper (especially no 
                 through paper 
                 short chain and 
               
               
                   
                 wicking or cockle). 
                   
                 multi-branched oils 
               
               
                   
                 Oil soluble dies and 
                   
                 have a sufficiently 
               
               
                   
                 pigments are required. 
                   
                 low viscosity. 
               
               
                   
                   
                   
                 ♦ Slow drying 
               
               
                 Micro- 
                 A microemulsion is a 
                 ♦ Stops ink bleed 
                 ♦ Viscosity higher 
                 ♦ All IJ series ink 
               
               
                 emulsion 
                 stable, self forming 
                 ♦ High dye 
                 than water 
                 jets 
               
               
                   
                 emulsion of oil, water, 
                 solubility 
                 ♦ Cost is slightly 
               
               
                   
                 and surfactant. The 
                 ♦ Water, oil, and 
                 higher than water 
               
               
                   
                 characteristic drop size 
                 amphiphilic soluble 
                 based ink 
               
               
                   
                 is less than 100 nm, 
                 dies can be used 
                 ♦ High surfactant 
               
               
                   
                 and is determined by 
                 ♦ Can stabilize 
                 concentration 
               
               
                   
                 the preferred curvature 
                 pigment 
                 required (around 
               
               
                   
                 of the surfactant. 
                 suspensions 
                 5%)