Patent Publication Number: US-6338547-B1

Title: Conductive PTFE bend actuator vented 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 US patent application serial numbers (USSN) are listed alongside the Australian applications from which the U.S. patent applications claim the right of priority. 
     
       
         
           
               
               
               
             
               
                   
               
               
                 CROSS-REFERENCED 
                 U.S. PATENT/PATENT 
                   
               
               
                 AUSTRALIAN 
                 APPLICATION 
               
               
                 PROVISIONAL 
                 (CLAIMING RIGHT OF 
               
               
                 PATENT 
                 PRIORITY FROM AUSTRALIAN 
                 DOCKET 
               
               
                 APPLICATION NO. 
                 PROVISIONAL APPLICATION) 
                 NO. 
               
               
                   
               
             
            
               
                 PO7991 
                 09/113,060 
                 ART01 
               
               
                 PO8505 
                 09/113,070 
                 ART02 
               
               
                 PO7988 
                 09/113,073 
                 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 
                  6,106,147 
                 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 
                 09/113,099 
                 IJ06 
               
               
                 PO8044 
                 09/113,084 
                 IJ07 
               
               
                 PO8063 
                 09/113,066 
                 IJ08 
               
               
                 PO8057 
                 09/112,778 
                 IJ09 
               
               
                 PO8056 
                 09/112,779 
                 IJ10 
               
               
                 PO8069 
                 09/113,077 
                 IJ11 
               
               
                 PO8049 
                 09/113,061 
                 IJ12 
               
               
                 PO8036 
                 09/112,818 
                 IJ13 
               
               
                 PO8048 
                 09/112,816 
                 IJ14 
               
               
                 PO8070 
                 09/112,772 
                 IJ15 
               
               
                 PO8067 
                 09/112,819 
                 IJ16 
               
               
                 PO8001 
                 09/112,815 
                 IJ17 
               
               
                 PO8038 
                 09/113,096 
                 IJ18 
               
               
                 PO8033 
                 09/113,068 
                 IJ19 
               
               
                 PO8002 
                 09/113,095 
                 IJ20 
               
               
                 PO8068 
                 09/112,808 
                 IJ21 
               
               
                 PO8062 
                 09/112,809 
                 IJ22 
               
               
                 PO8034 
                 09/112,780 
                 IJ23 
               
               
                 PO8039 
                 09/113,083 
                 IJ24 
               
               
                 PO8041 
                 09/113,121 
                 IJ25 
               
               
                 PO8004 
                 09/113,122 
                 IJ26 
               
               
                 PO8037 
                 09/112,793 
                 IJ27 
               
               
                 PO8043 
                 09/112,794 
                 IJ28 
               
               
                 PO8042 
                 09/113,128 
                 IJ29 
               
               
                 PO8064 
                 09/113,127 
                 IJ30 
               
               
                 PO9389 
                 09/112,756 
                 IJ31 
               
               
                 PO9391 
                 09/112,755 
                 IJ32 
               
               
                 PP0888 
                 09/112,754 
                 IJ33 
               
               
                 PP0891 
                 09/112,811 
                 IJ34 
               
               
                 PP0890 
                 09/112,812 
                 IJ35 
               
               
                 PP0873 
                 09/112,813 
                 IJ36 
               
               
                 PP0993 
                 09/112,814 
                 IJ37 
               
               
                 PP0890 
                 09/112,764 
                 IJ38 
               
               
                 PP1398 
                 09/112,765 
                 IJ39 
               
               
                 PP2592 
                 09/112,767 
                 IJ40 
               
               
                 PP2593 
                 09/112,768 
                 IJ41 
               
               
                 PP3991 
                 09/112,807 
                 IJ42 
               
               
                 PP3987 
                 09/112,806 
                 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 
                 09/112,828 
                 IJM05 
               
               
                 PO8065 
                  6,071,750 
                 IJM06 
               
               
                 PO8055 
                 09/113,108 
                 IJM07 
               
               
                 PO8053 
                 09/113,109 
                 IJM08 
               
               
                 PO8078 
                 09/113,123 
                 IJM09 
               
               
                 PO7933 
                 09/113,114 
                 IJM10 
               
               
                 PO7950 
                 09/113,115 
                 IJM11 
               
               
                 PO7949 
                 09/113,129 
                 IJM12 
               
               
                 PO8060 
                 09/113,124 
                 IJM13 
               
               
                 PO8059 
                 09/113,125 
                 IJM14 
               
               
                 PO8073 
                 09/113,126 
                 IJM15 
               
               
                 PO8076 
                 09/113,119 
                 IJM16 
               
               
                 PO8075 
                 09/113,120 
                 IJM17 
               
               
                 PO8079 
                 09/113,221 
                 IJM18 
               
               
                 PO8050 
                 09/113,116 
                 IJM19 
               
               
                 PO8052 
                 09/113,118 
                 IJM20 
               
               
                 PO7948 
                 09/113,117 
                 IJM21 
               
               
                 PO7951 
                 09/113,113 
                 IJM22 
               
               
                 PO8074 
                 09/113,130 
                 IJM23 
               
               
                 PO7941 
                 09/113,110 
                 IJM24 
               
               
                 PO8077 
                 09/113,112 
                 IJM25 
               
               
                 PO8058 
                 09/113,087 
                 IJM26 
               
               
                 PO8051 
                 09/113,074 
                 IJM27 
               
               
                 PO8045 
                  6,111,754 
                 IJM28 
               
               
                 PO7952 
                 09/113,088 
                 IJM29 
               
               
                 PO8046 
                 09/112,771 
                 IJM30 
               
               
                 PO9390 
                 09/112,769 
                 IJM31 
               
               
                 PO9392 
                 09/112,770 
                 IJM32 
               
               
                 PP0889 
                 09/112,798 
                 IJM35 
               
               
                 PP0887 
                 09/112,801 
                 IJM36 
               
               
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                 09/112,800 
                 IJM37 
               
               
                 PP0874 
                 09/112,799 
                 IJM38 
               
               
                 PP1396 
                 09/113,098 
                 IJM39 
               
               
                 PP3989 
                 09/112,833 
                 IJM40 
               
               
                 PP2591 
                 09/112,832 
                 IJM41 
               
               
                 PP3990 
                 09/112,831 
                 IJM42 
               
               
                 PP3986 
                 09/112,830 
                 IJM43 
               
               
                 PP3984 
                 09/112,836 
                 IJM44 
               
               
                 PP3982 
                 09/112,835 
                 IJM45 
               
               
                 PP0895 
                 09/113,102 
                 IR01 
               
               
                 PP0870 
                 09/113,106 
                 IR02 
               
               
                 PP0869 
                 09/113,105 
                 IR04 
               
               
                 PP0887 
                 09/113,104 
                 IR05 
               
               
                 PP0885 
                 09/112,810 
                 IR06 
               
               
                 PP0884 
                 09/112,766 
                 IR10 
               
               
                 PP0886 
                 09/113,085 
                 IR12 
               
               
                 PP0871 
                 09/113,086 
                 IR13 
               
               
                 PP0876 
                 09/113,094 
                 IR14 
               
               
                 PP0877 
                 09/112,760 
                 IR16 
               
               
                 PP0878 
                 09/112,773 
                 IR17 
               
               
                 PP0879 
                 09/112,774 
                 IR18 
               
               
                 PP0883 
                 09/112,775 
                 IR19 
               
               
                 PP0880 
                  6,152,619 
                 IR20 
               
               
                 PP0881 
                 09/113,092 
                 IR21 
               
               
                 PO8006 
                  6,087,638 
                 MEMS02 
               
               
                 PO8007 
                 09/113,093 
                 MEMS03 
               
               
                 PO8008 
                 09/113,062 
                 MEMS04 
               
               
                 PO8010 
                  6,041,600 
                 MEMS05 
               
               
                 PO8011 
                 09/113,082 
                 MEMS06 
               
               
                 PO7947 
                  6,067,797 
                 MEMS07 
               
               
                 PO7944 
                 09/113,080 
                 MEMS09 
               
               
                 PO7946 
                  6,044,646 
                 MEMS10 
               
               
                 PO9393 
                 09/113,065 
                 MEMS11 
               
               
                 PP0875 
                 09/113,078 
                 MEMS12 
               
               
                 PP0894 
                 09/113,075 
                 MEMS13 
               
               
                   
               
            
           
         
       
     
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     FIELD OF THE INVENTION 
     The present invention relates to ink jet printing and in particular discloses a conductive PTFE bend activator vented ink jet printer. 
     The present invention further relates to the field of drop on demand ink jet printing. 
     BACKGROUND OF THE INVENTION 
     Many different types of printing have been invented, a large number of which are presently in use. The known forms of print have a variety of methods for marking the print media with a relevant marking media. Commonly used forms of printing include offset printing, laser printing and copying devices, dot matrix type impact printers, thermal paper printers, film recorders, thermal wax printers, dye sublimation printers and ink jet printers both of the drop on demand and continuous flow type. Each type of printer has its own advantages and problems when considering cost, speed, quality, reliability, simplicity of construction and operation etc. 
     In recent years, the field of ink jet printing, wherein each individual pixel of ink is derived from one or more ink nozzles has become increasingly popular primarily due to its inexpensive and versatile nature. 
     Many different techniques 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 disclosed ink jet printing techniques rely upon the activation of an electrothermal actuator which results in the creation of a bubble in a constricted space, such as a nozzle, which thereby causes the ejection of ink from an aperture connected to the confined space onto a relevant print media. Printing devices utilizing the electro-thermal actuator are manufactured by manufacturers such as Canon and Hewlett Packard. 
     As can be seen from the foregoing, many different types of printing technologies are available. Ideally, a printing technology should have a number of desirable attributes. These include inexpensive construction and operation, high speed operation, safe and continuous long term operation etc. Each technology may have its own advantages and disadvantages in the areas of cost, speed, quality, reliability, power usage, simplicity of construction operation, durability and consumables. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an alternative form of inkjet printer having an energy efficient nozzle actuator design which also can be simply constructed. 
     In accordance with a first aspect of the present invention, there is provided an ink jet nozzle comprising a nozzle chamber having an ink ejection port in one wall of the chamber, an ink supply source interconnected to the nozzle chamber and a thermal actuator activated to eject ink from the nozzle chamber via the ink ejection port, the thermal actuator comprising two layers of actuator material having a high coefficient of thermal expansion, a top layer being substantially non conductive and a bottom layer being conductive, the thermal actuator being activated by means of passing a current through the bottom layer so as to cause it to expand relative to the top layer, which is cooled by the chamber ink. Further, the bottom layer comprises portions being conductive and portions being non-conductive such that a circuit is formed for the heating of the bottom layer through the interaction of the conductive and non-conductive portions. Preferably, the resistive circuit is created having predetermined area of low circuit cross-sectional area so as to produce high levels of heating of the actuators in those areas. Advantageously, the non-conductive portions are formed from the same material as the top layer. 
     In accordance with a second aspect of the present invention, there is provided an ink jet nozzle comprising a nozzle chamber having an ink ejection port in one wall of the chamber, an ink supply source interconnected to the nozzle chamber and a thermal actuator activated to eject ink from the nozzle chamber via the ink ejection port, the thermal actuator being activated by means of passing a current through the bottom layer so as to cause it to expand relative to the top layer. Further, the bottom of the actuator can have a hydrophobic surface and during operation the hydrophobic surface causes an air bubble to form under the thermal actuator. The bottom surface of the actuator can be air vented so as to reduce the actuation energy required to eject ink from the nozzle chamber. Advantageously, the air venting comprises a series of small holes underneath the actuator, the holes being interconnected to an air supply channel for the supply of air to the back of the actuator. Further, the area around the bottom surface of the actuator can be constructed from hydrophobic material. The holes are of a size such that, during operation, any fluid is retained within the nozzle chamber. Preferably, the actuator is attached at one end to the nozzle chamber and the holes are located near the attached end and the actuator is constructed from polytetrafluoroethylene. Further, the actuator can have a bottom layer treated in portions so as to form a conductive material. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Notwithstanding any other forms which may fall within the scope of the present invention, preferred forms of the invention will now be described, by way of example only, with reference to the accompanying drawings which: 
     FIG. 1 is a cut out topside view illustrating two adjoining inject nozzles constructed in accordance with the preferred embodiment; 
     FIG. 2 is an exploded perspective view illustrating the construction of a single inject nozzle in accordance with the preferred embodiment; 
     FIG. 3 is a sectional view through the nozzles of FIG. 1; 
     FIG. 4 is a sectional view through the line IV-IV′ of FIG. 3; 
     FIG. 5 provides a legend of the materials indicated in FIG. 6 to  19 ; and 
     FIG. 6 to FIG. 19 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 nozzle is provided having a thermally based actuator which is highly energy efficient. The thermal actuator is located within a chamber filled with ink and relies upon the thermal expansion of materials when an electric current is being passed through them to activate the actuator thereby causing the ejection of ink out of a nozzle provided in the nozzle chamber. 
     Turning to the figures, in FIG. 1, there are illustrated two adjoining inkjet nozzles  1  constructed in accordance with the preferred embodiment, with FIG. 2 showing an exploded perspective and FIG. 4 showing various sectional views. Each nozzle  1 , can be constructed as part of an array of nozzles on a silicon wafer device and can be constructed utilising semiconductor processing techniques in addition to micro machining and micro fabrication process technology (MEMS) and a full familiarity with these technologies is hereinafter assumed. 
     A nozzle chamber  10  includes a ink ejection port  11  for the ejection of ink from within the nozzle chamber. Ink is supplied via an inlet port  12  which has a grill structure fabricated from a series of posts  14 , the grill acting to filter out foreign bodies within the ink supply and also to provide stability to the nozzle chamber structure. Inside the nozzle chamber is constructed a thermal actuator device  16  which is interconnected to an electric circuit (not shown) which, when thermally actuated, acts as a paddle bending upwards so as to cause the ejection of ink from each ink ejection port  11 . A series of etchant holes e.g.  18  are also provided in the top of nozzle chamber  10 , the holes  18  being provided for manufacturing purposes only so to allow a sacrificial etchant to easily etch away the internal portions of nozzle chamber  10 . The etchant ports  18  are of a sufficiently small diameter so that the resulting surface tension holds the ink within chamber  10  such that no ink leaks out via ports  18 . 
     The thermal actuator  16  is composed primarily of polytetrafluoroethylene (PTFE) which is a generally hydrophobic material. The top layer of the actuator  16  is treated or coated so as to make it hydrophilic and thereby attract water/ink via inlet port  12 . Suitable treatments include plasma exposure in an ammonia atmosphere. The bottom surface remains hydrophobic and repels the water from the underneath surface of the actuator  16 . Underneath the actuator  16  is provided a further surface  19  also composed of a hydrophobic material such as PTFE. The surface  19  has a series of holes  20  in it which allow for the flow of air into the nozzle chamber  10 . The diameter of the nozzle holes  20  again being of such a size so as to restrict the flow of fluid out of the nozzle chamber via surface tension interactions out of the nozzle chamber. 
     The surface  19  is separated from a lower level  23  by means of a series of spaced apart posts e.g.  22  which can be constructed when constructing the layer  19  utilising an appropriate mask. The nozzle chamber  10 , but for grill inlet port  12 , is walled on its sides by silicon nitride walls e.g.  25 , 26 . An air inlet port is formed between adjacent nozzle chambers such that air is free to flow between the walls  25 , 28 . Hence, air is able to flow down channel  29  and along channel  30  and through holes e.g.  20  in accordance with any fluctuating pressure influences. 
     The air flow acts to reduce the vacuum on the back surface of actuator  16  during operation. As a result, less energy is required for the movement of the actuator  16 . In operation, the actuator  16  is thermally actuated so as to move upwards and cause ink ejection. As a result, air flows in along channels  29 , 30  and through the holes e.g.  20  into the bottom area of actuator  16 . Upon deactivation of the actuator  16 , the actuator lowers with a corresponding airflow out of port  20  along channel  30  and out of channel  29 . Any fluid within nozzle chamber  10  is firstly repelled by the hydrophobic nature of the bottom side of the surface of actuator  16  in addition to the top of the surface  19  which is again hydrophobic. As noted previously the limited size holes e.g.  20  further stop the fluid from passing the holes  20  as a result of surface tension characteristics. 
     A further preferable feature of nozzle chamber  10  is the utilisation of the nitride posts  14  to also clamp one end of the surfaces  16  and  19  firmly to bottom surface  20  thereby reducing the likelihood delaminating during operation. 
     In FIG. 2, there is illustrated an exploded perspective view of a single nozzle  1 . The exploded perspective view illustrates the form of construction of each layer of a simple nozzle  1 . The nozzle arrangement can be constructed on a base silicon wafer  34  having a top glass layer which includes the various drive and control circuitry and which, for example, can comprise a two level metal CMOS layer with the various interconnects (not shown). On top of the layer  35  is first laid out a nitride passivation layer  23  of approximately one micron thickness which includes a number of vias (not shown) for the interconnection of the subsequent layers to the CMOS layer  35 . The nitride layer is provided primarily to protect lower layers from corrosion or etching, especially where sacrificial etchants are utilized. Next, a one micron PTFE layer  19  is constructed having the aforementioned holes e.g.  20  and posts  22 . The structure of the PTFE layer  19  can be formed by first laying down a sacrificial glass layer (not shown) onto which the PTFE layer  19  is deposited. The PTFE layer  19  includes various features, for example, a lower ridge portion  38  in addition to a hole  39  which acts as a via for the subsequent material layers. 
     The actuator proper is formed from two PTFE layers  40 , 41 . The lower PTFE layer  40  is made conductive. The PTFE layer  40  can be made conductive utilising a number of different techniques including: 
     (i) Doping the PTFE layer with another material so as to make it conductive. 
     (ii) Embedding within the PTFE layer a series of quantum wires constructed from such a material as carbon nano-tubes created in a mesh form. (“Individual single-wall carbon nano-tubes as quantum wires” by Tans et al Nature, Volume 386, Apr. 3rd 1997 at pages 474-477). The PTFE layer  40  includes certain cut out portions e.g.  43  so that a complete circuit is formed around the PTFE actuator  40 . The cut out portions can be optimised so as to regulate the resistive heating of the layer  40  by means of providing constricted portions so as to thereby increase the heat generated in various “hot spots” as required. A space is provided between the PTFE layer  19  and the PTFE layer  40  through the utilisation of an intermediate sacrificial glass layer (not shown). 
     On top of the PTFE layer  40  is deposited a second PTFE layer  41  which can be a standard non conductive PTFE layer and can include filling in those areas in the lower PTFE layer e.g.  43  which are not conductive. The top of the PTFE layer is further treated or coated to make it hydrophilic. 
     Next, a nitride layer can be deposited to form the nozzle chamber proper. The nitride layer can be formed by first laying down a sacrificial glass layer and etching the glass layer to form walls e.g.  25 ,  26  and grilled portion e.g.  14 . Preferably, the mask utilised results a first anchor portion  45  which mates with the hole  39  in layer  19  so as to fix the layer  19  to the nitride layer  23 . Additionally, the bottom surface of the grill  14  meets with a corresponding step  47  in the PTFE layer  41  so as to clamp the end portion of the PTFE layers  41 , 40  and  39  to the wafer surface so as to guard against delamination. Next, a top nitride layer  50  can be formed having a number of holes e.g.  18  and nozzle hole  11  around which a rim can be etched through etching of the nitride layer  50 . Subsequently, the various sacrificial layers can be etched away so as to release the structure of the thermal actuator. 
     Obviously, large arrays of inkjet nozzles  10  can be created side by side on a single wafer. The ink can be supplied via ink channels etched through the wafer utilising a high density low pressure plasma etching system such as that supplied by Surface Technology Systems of the United Kingdom. 
     The foregoing describes only one embodiment of the invention and many variations of the embodiment will be obvious for a person skilled in the art of semi conductor, micro mechanical fabrication. Certainly, various other materials can be utilised in the construction of the various layers. 
     One form of detailed manufacturing process which can be used to fabricate monolithic ink jet printheads operating in accordance with the principles taught by the present embodiment can proceed utilizing the following steps: 
     1. Using a double sided polished wafer, complete drive transistors, data distribution, and timing circuits using a 0.5 micron, one poly, 2 metal CMOS process. Relevant features of the wafer at this step are shown in FIG.  6 . For clarity, these diagrams may not be to scale, and may not represent a cross section though any single plane of the nozzle. FIG. 5 is a key to representations of various materials in these manufacturing diagrams, and those of other cross referenced ink jet configurations. 
     2. Deposit 1 micron of low stress nitride. This acts as a barrier to prevent ink diffusion through the silicon dioxide of the chip surface. 
     3. Deposit 2 microns of sacrificial material (e.g. polyimide). 
     4. Etch the sacrificial layer using Mask  1 . This mask defines the PTFE venting layer support pillars and anchor point. This step is shown in FIG.  7 . 
     5. Deposit 2 microns of PTFE. 
     6. Etch the PTFE using Mask  2 . This mask defines the edges of the PTFE venting layer, and the holes in this layer. This step is shown in FIG.  8 . 
     7. Deposit 3 micron of sacrificial material (e.g. polyimide). 
     8. Etch the sacrificial layer and CMOS passivation layer using Mask  3 . This mask defines the actuator contacts. This step is shown in FIG.  9 . 
     9. Deposit 1 micron of conductive PTFE. Conductive PTFE can be formed by doping the PTFE with a conductive material, such as extremely fine metal or graphitic filaments, or fine metal particles, and so forth. The PIFE should be doped so that the resistance of the PTFE conductive heater is sufficiently low so that the correct amount of power is dissipated by the heater when the drive voltage is applied. However, the conductive material should be a small percentage of the PTFE volume, so that the coefficient of thermal expansion is not significantly reduced. Carbon nanotubes can provide significant conductivity at low concentrations. This step is shown in FIG.  10 . 
     10. Etch the conductive PTFE using Mask  4 . This mask defines the actuator conductive regions. This step is shown in FIG.  11 . 
     11. Deposit 1 micron of PTFE. 
     12. Etch the PTFE down to the sacrificial layer using Mask  5 . This mask defines the actuator paddle. This step is shown in FIG.  12 . 
     13. Wafer probe. All electrical connections are complete at this point, and the chips are not yet separated. 
     14. Plasma process the PTFE to make the top and side surfaces of the paddle hydrophilic. This allows the nozzle chamber to fill by capillarity. 
     15. Deposit 10 microns of sacrificial material. 
     16. Etch the sacrificial material down to nitride using Mask  6 . This mask defines the nozzle chamber and inlet filter. This step is shown in FIG.  13 . 
     17. Deposit 3 microns of PECVD glass. This step is shown in FIG.  14 . 
     18. Etch to a depth of 1 micron using Mask  7 . This mask defines the nozzle rim. This step is shown in FIG.  15 . 
     19. Etch down to the sacrificial layer using Mask  8 . This mask defines the nozzle and the sacrificial etch access holes. This step is shown in FIG.  16 . 
     20. Back-etch completely through the silicon wafer (with, for example, an ASE Advanced Silicon Etcher from Surface Technology Systems) using Mask  9 . This mask defines the ink inlets which are etched through the wafer. The wafer is also diced by this etch. This step is shown in FIG.  17 . 
     21. Back-etch the CMOS oxide layers and subsequently deposited nitride layers through to the sacrificial layer using the back-etched silicon as a mask. 
     22. 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.  18 . 
     23. 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. 
     24. 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. 
     25. Hydrophobize the front surface of the printheads. 
     26. Fill the completed printheads with ink and test them. A filled nozzle is shown in FIG.  19 . 
     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. 
     The presently disclosed ink jet printing technology is potentially suited to a wide range of printing systems including: color and monochrome office printers, short run digital printers, high speed digital printers, offset press supplemental printers, low cost scanning printers, high speed pagewidth printers, notebook computers with inbuilt pagewidth printers, portable color and monochrome printers, color and monochrome copiers, color and monochrome facsimile machines, combined printer, facsimile and copying machines, label printers, large format plotters, photograph copiers, printers for digital photographic ‘minilabs’, video printers, PHOTO CD (PHOTO CD is a registered trademark of the Eastman Kodak Company) printers, portable printers for PDAs, wallpaper printers, indoor sign printers, billboard printers, fabric printers, camera printers and fault tolerant commercial printer arrays. 
     Ink Jet Technologies 
     The embodiments of the invention use an ink jet printer type device. Of course many different devices could be used. However presently popular ink jet printing technologies are unlikely to be suitable. 
     The most significant problem with thermal ink jet is power consumption. This is approximately 100 times that required for high speed, and stems from the energy-inefficient means of drop ejection. This involves the rapid boiling of water to produce a vapor bubble which expels the ink. Water has a very high heat capacity, and must be superheated in thermal ink jet applications. This leads to an efficiency of around 0.02%, from electricity input to drop momentum (and increased surface area) out. 
     The most significant problem with piezoelectric ink jet is size and cost. Piezoelectric crystals have a very small deflection at reasonable drive voltages, and therefore require a large area for each nozzle. Also, each piezoelectric actuator must be connected to its drive circuit on a separate substrate. This is not a significant problem at the current limit of around 300 nozzles per printhead, but is a major impediment to the fabrication of pagewidth printheads with 19,200 nozzles. 
     Ideally, the ink jet technologies used meet the stringent requirements of in-camera digital color printing and other high quality, high speed, low cost printing applications. To meet the requirements of digital photography, new ink jet technologies have been created. The target features include: 
     low power (less than 10 Watts) 
     high resolution capability (1,600 dpi or more) 
     photographic quality output 
     low manufacturing cost 
     small size (pagewidth times minimum cross section) 
     high speed (&lt;2 seconds per page). 
     All of these features can be met or exceeded by the ink jet systems described below with differing levels of difficulty. Forty-five different ink jet technologies have been developed by the Assignee to give a wide range of choices for high volume manufacture. These technologies form part of separate applications assigned to the present Assignee as set out in the table under the heading Cross References to Related Applications. 
     The ink jet designs shown here are suitable for a wide range of digital printing systems, from battery powered one-time use digital cameras, through to desktop and network printers, and through to commercial printing systems. 
     For ease of manufacture using standard process equipment, the printhead is designed to be a monolithic 0.5 micron CMOS chip with MEMS post processing. For color photographic applications, the printhead is 100 mm long, with a width which depends upon the ink jet type. The smallest printhead designed is IJ38, which is 0.35 mm wide, giving a chip area of 35 square mm. The printheads each contain 19,200 nozzles plus data and control circuitry. 
     Ink is supplied to the back of the printhead by injection molded plastic ink channels. The molding requires 50 micron features, which can be created using a lithographically micromachined insert in a standard injection molding tool. Ink flows through holes etched through the wafer to the nozzle chambers fabricated on the front surface of the wafer. The 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 which match the docket numbers in the table under the heading Cross References to Related Applications. 
     Other ink jet configurations can readily be derived from these forty-five examples by substituting alternative configurations along one or more of the 11 axes. Most of the IJ01 to IJ45 examples can be made into ink jet printheads with characteristics superior to any currently available ink jet technology. 
     Where there are prior art examples known to the inventor, one or more of these examples are listed in the examples column of the tables below. The IJ01 to IJ45 series are also listed in the examples column. In some cases, a printer 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. 
     
       
         
           
               
            
               
                   
               
               
                 ACTUATOR MECHANISM (APPLIED ONLY TO SELECTED INK DROPS) 
               
            
           
           
               
               
               
               
               
            
               
                   
                 Description 
                 Advantages 
                 Disadvantages 
                 Examples 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                 Thermal 
                 An electrothermal 
                 Large force 
                 High power 
                 Canon Bubblejet 
               
               
                 bubble 
                 heater heats the ink to 
                 generated 
                 Ink carrier 
                 1979 Endo et al GB 
               
               
                   
                 above boiling point, 
                 Simple 
                 limited to water 
                 patent 2,007,162 
               
               
                   
                 transferring significant 
                 construction 
                 Low efficiency 
                 Xerox heater-in- 
               
               
                   
                 heat to the aqueous 
                 No moving parts 
                 High 
                 pit 1990 Hawkins et 
               
               
                   
                 ink. A bubble 
                 Fast operation 
                 temperatures 
                 al U.S. Pat. No. 4,899,181 
               
               
                   
                 nucleates and quickly 
                 Small chip area 
                 required 
                 Hewlett-Packard 
               
               
                   
                 forms, expelling the 
                 required for actuator 
                 High mechanical 
                 TIJ 1982 Vaught et 
               
               
                   
                 ink. 
                   
                 stress 
                 al U.S. Pat. No. 4,490,728 
               
               
                   
                 The efficiency of the 
                   
                 Unusual 
               
               
                   
                 process is low, with 
                   
                 materials required 
               
               
                   
                 typically less than 
                   
                 Large drive 
               
               
                   
                 0.05% of the electrical 
                   
                 transistors 
               
               
                   
                 energy being 
                   
                 Cavitation causes 
               
               
                   
                 transformed into 
                   
                 actuator failure 
               
               
                   
                 kinetic energy of the 
                   
                 Kogation reduces 
               
               
                   
                 drop. 
                   
                 bubble formation 
               
               
                   
                   
                   
                 Large print heads 
               
               
                   
                   
                   
                 are difficult to 
               
               
                   
                   
                   
                 fabricate 
               
               
                 Piezo- 
                 A piezoelectric crystal 
                 Low power 
                 Very large area 
                 Kyser et al U.S. Pat. No. 
               
               
                 electric 
                 such as lead 
                 consumption 
                 required for actuator 
                 3,946,398 
               
               
                   
                 lanthanum zirconate 
                 Many ink types 
                 Difficult to 
                 Zoltan U.S. Pat. No. 
               
               
                   
                 (PZT) is electrically 
                 can be used 
                 integrate with 
                 3,683,212 
               
               
                   
                 activated, and either 
                 Fast operation 
                 electronics 
                 1973 Stemme 
               
               
                   
                 expands, shears, or 
                 High efficiency 
                 High voltage 
                 U.S. Pat. No. 3,747,120 
               
               
                   
                 bends to apply 
                   
                 drive transistors 
                 Epson Stylus 
               
               
                   
                 pressure to the ink, 
                   
                 required 
                 Tektronix 
               
               
                   
                 ejecting drops. 
                   
                 Full pagewidth 
                 IJ04 
               
               
                   
                   
                   
                 print heads 
               
               
                   
                   
                   
                 impractical due to 
               
               
                   
                   
                   
                 actuator size 
               
               
                   
                   
                   
                 Requires 
               
               
                   
                   
                   
                 electrical poling in 
               
               
                   
                   
                   
                 high field strengths 
               
               
                   
                   
                   
                 during manufacture 
               
               
                 Electro- 
                 An electric field is 
                 Low power 
                 Low maximum 
                 Seiko Epson, 
               
               
                 strictive 
                 used to activate 
                 consumption 
                 strain (approx. 
                 Usui et all JP 
               
               
                   
                 electrostriction in 
                 Many ink types 
                 0.01%) 
                 253401/96 
               
               
                   
                 relaxor materials such 
                 can be used 
                 Large area 
                 IJ04 
               
               
                   
                 as lead lanthanum 
                 Low thermal 
                 required for actuator 
               
               
                   
                 zirconate titanate 
                 expansion 
                 due to low strain 
               
               
                   
                 (PLZT) or lead 
                 Electric field 
                 Response speed 
               
               
                   
                 magnesium niobate 
                 strength required 
                 is marginal (˜10 
               
               
                   
                 (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 
                 U.S. Pat. No. 4,799,068 
               
               
                 on ink 
                 whereupon 
                 Low temperature 
                 May be damaged 
                 1989 Miura et al, 
               
               
                   
                 electrostatic attraction 
                   
                 by sparks due to air 
                 U.S. Pat. No. 4,810,954 
               
               
                   
                 accelerates the ink 
                   
                 breakdown 
                 Tone-jet 
               
               
                   
                 towards the print 
                   
                 Required field 
               
               
                   
                 medium. 
                   
                 strength increases as 
               
               
                   
                   
                   
                 the drop size 
               
               
                   
                   
                   
                 decreases 
               
               
                   
                   
                   
                 High voltage 
               
               
                   
                   
                   
                 drive transistors 
               
               
                   
                   
                   
                 required 
               
               
                   
                   
                   
                 Electrostatic field 
               
               
                   
                   
                   
                 attracts dust 
               
               
                 Permanent 
                 An electromagnet 
                 Low power 
                 Complex 
                 IJ07, IJ10 
               
               
                 magnet 
                 directly attracts a 
                 consumption 
                 fabrication 
               
               
                 electro- 
                 permanent magnet, 
                 Many ink types 
                 Permanent 
               
               
                 magnetic 
                 displacing ink and 
                 can be used 
                 magnetic material 
               
               
                   
                 causing drop ejection. 
                 Fast operation 
                 such as Neodymium 
               
               
                   
                 Rare earth magnets 
                 High efficiency 
                 Iron Boron (NdFeB) 
               
               
                   
                 with a field strength 
                 Easy extension 
                 required. 
               
               
                   
                 around 1 Tesla can be 
                 from single nozzles 
                 High local 
               
               
                   
                 used. Examples are: 
                 to pagewidth print 
                 currents required 
               
               
                   
                 Samarium Cobalt 
                 heads 
                 Copper 
               
               
                   
                 (SaCo) and magnetic 
                   
                 metalization should 
               
               
                   
                 materials in the 
                   
                 be used for long 
               
               
                   
                 neodymium iron boron 
                   
                 electromigration 
               
               
                   
                 family (NdFeB, 
                   
                 lifetime and low 
               
               
                   
                 NdDyFeBNb, 
                   
                 resistivity 
               
               
                   
                 NdDyFeB, etc) 
                   
                 Pigmented inks 
               
               
                   
                   
                   
                 are usually 
               
               
                   
                   
                   
                 infeasible 
               
               
                   
                   
                   
                 Operating 
               
               
                   
                   
                   
                 temperature limited 
               
               
                   
                   
                   
                 to the Curie 
               
               
                   
                   
                   
                 temperature (around 
               
               
                   
                   
                   
                 540 K) 
               
               
                 Soft 
                 A solenoid induced a 
                 Low power 
                 Complex 
                 IJ01, IJ05, IJ08, 
               
               
                 magnetic 
                 magnetic field in a soft 
                 consumption 
                 fabrication 
                 IJ10, IJ12, IJ14, 
               
               
                 core electro- 
                 magnetic core or yoke 
                 Many ink types 
                 Materials not 
                 IJ15, IJ17 
               
               
                 magnetic 
                 fabricated from a 
                 can be used 
                 usually present in a 
               
               
                   
                 ferrous material such 
                 Fast operation 
                 CMOS fab such as 
               
               
                   
                 as electroplated iron 
                 High efficiency 
                 NiFe, CoNiFe, or 
               
               
                   
                 alloys such as CoNiFe 
                 Easy extension 
                 CoFe are required 
               
               
                   
                 [1], CoFe, or NiFe 
                 from single nozzles 
                 High local 
               
               
                   
                 alloys. Typically, the 
                 to pagewidth print 
                 currents required 
               
               
                   
                 soft magnetic material 
                 heads 
                 Copper 
               
               
                   
                 is in two parts, which 
                   
                 metalization should 
               
               
                   
                 are normally held 
                   
                 be used for long 
               
               
                   
                 apart by a spring. 
                   
                 electromigration 
               
               
                   
                 When the solenoid is 
                   
                 lifetime and low 
               
               
                   
                 actuated, the two parts 
                   
                 resistivity 
               
               
                   
                 attract, displacing the 
                   
                 Electroplating is 
               
               
                   
                 ink. 
                   
                 required 
               
               
                   
                   
                   
                 High saturation 
               
               
                   
                   
                   
                 flux density is 
               
               
                   
                   
                   
                 required (2.0-2.1 T 
               
               
                   
                   
                   
                 is achievable with 
               
               
                   
                   
                   
                 CoNiFe [1]) 
               
               
                 Lorenz 
                 The Lorenz force 
                 Low power 
                 Force acts as a 
                 IJ06, IJ11, IJ13, 
               
               
                 force 
                 acting on a current 
                 consumption 
                 twisting motion 
                 IJ16 
               
               
                   
                 carrying wire in a 
                 Many ink types 
                 Typically, only a 
               
               
                   
                 magnetic field is 
                 can be used 
                 quarter of the 
               
               
                   
                 utilized. 
                 Fast operation 
                 solenoid length 
               
               
                   
                 This allows the 
                 High efficiency 
                 provides force in a 
               
               
                   
                 magnetic field to be 
                 Easy extension 
                 useful direction 
               
               
                   
                 supplied externally to 
                 from single nozzles 
                 High local 
               
               
                   
                 the print head, for 
                 to pagewidth print 
                 currents required 
               
               
                   
                 example with rare 
                 heads 
                 Copper 
               
               
                   
                 earth permanent 
                   
                 metalization should 
               
               
                   
                 magnets. 
                   
                 be used for long 
               
               
                   
                 Only the current 
                   
                 electromigration 
               
               
                   
                 carrying wire need be 
                   
                 lifetime and low 
               
               
                   
                 fabricated on the print- 
                   
                 resistivity 
               
               
                   
                 head, simplifying 
                   
                 Pigmented inks 
               
               
                   
                 materials 
                   
                 are usually 
               
               
                   
                 requirements. 
                   
                 infeasible 
               
               
                 Magneto- 
                 The actuator uses the 
                 Many ink types 
                 Force acts as a 
                 Fischenbeck, 
               
               
                 striction 
                 giant magnetostrictive 
                 can be used 
                 twisting motion 
                 U.S. Pat. No. 4,032,929 
               
               
                   
                 effect of materials 
                 Fast operation 
                 Unusual 
                 IJ25 
               
               
                   
                 such as Terfenol-D (an 
                 Easy extension 
                 materials such as 
               
               
                   
                 alloy of terbium, 
                 from single nozzles 
                 Terfenol-D are 
               
               
                   
                 dysprosium and iron 
                 to pagewidth print 
                 required 
               
               
                   
                 developed at the Naval 
                 heads 
                 High local 
               
               
                   
                 Ordnance Laboratory, 
                 High force is 
                 currents required 
               
               
                   
                 hence Ter-Fe-NOL). 
                 available 
                 Copper 
               
               
                   
                 For best efficiency, the 
                   
                 metalization should 
               
               
                   
                 actuator should be pre- 
                   
                 be used for long 
               
               
                   
                 stressed to approx. 8 
                   
                 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 
               
               
                 Conductive 
                 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 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
            
               
                   
               
               
                 BASIC OPERATION MODE 
               
            
           
           
               
               
               
               
               
            
               
                   
                 Description 
                 Advantages 
                 Disadvantages 
                 Examples 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                 Actuator 
                 This is the simplest mode of 
                 Simple operation 
                 Drop repetition rate is usually 
                 Thermal ink jet 
               
               
                 directly pushes 
                 operation: the actuator directly 
                 No external fields required 
                 limited to around 10 kHz. How- 
                 Piezoelectric ink jet 
               
               
                 ink 
                 supplies sufficient kinetic energy 
                 Satellite drops can be avoided if 
                 ever, this is not fundamental to 
                 IJ01, IJ02, IJ03, IJ04, IJ05, IJ06, 
               
               
                   
                 to expel the drop. The drop must 
                 drop velocity is less than 4 m/s 
                 the method, but is related to the 
                 IJ07, IJ09, IJ11, IJ12, IJ14, IJ16, 
               
               
                   
                 have a sufficient velocity to 
                 Can be efficient, depending 
                 refill method normally used 
                 IJ20, IJ22, IJ23, IJ24, IJ25, IJ26, 
               
               
                   
                 overcome the surface tension. 
                 upon the actuator used 
                 All of the drop kinetic energy 
                 IJ27, IJ28, IJ29, IJ30, IJ31, IJ32, 
               
               
                   
                   
                   
                 must be provided by the actuator 
                 IJ33, IJ34, IJ35, IJ36, IJ37, IJ38, 
               
               
                   
                   
                   
                 Satellite drops usually form if 
                 IJ39, IJ40, IJ41, IJ42, IJ43, IJ44 
               
               
                   
                   
                   
                 drop velocity is greater than 
               
               
                   
                   
                   
                 4.5 m/s 
               
               
                 Proximity 
                 The drops to be printed are 
                 Very simple print head fabrica- 
                 Requires close proximity 
                 Silverbrook, EP 0771 658 A2 
               
               
                   
                 selected by some manner (e.g. 
                 tion can be used 
                 between the print head and the 
                 and related patent applications 
               
               
                   
                 thermally induced surface 
                 The drop selection means does 
                 print media or transfer roller 
               
               
                   
                 tension reduction of pressurized 
                 not need to provide the energy 
                 May require two print heads 
               
               
                   
                 ink). Selected drops are 
                 required to separate the drop 
                 printing alternate rows of the 
               
               
                   
                 separated from the ink in the 
                 from the nozzle 
                 image 
               
               
                   
                 nozzle by contract with the 
                   
                 Monolithic color print heads are 
               
               
                   
                 print medium or a transfer 
                   
                 difficult 
               
               
                   
                 roller. 
               
               
                 Electrostatic 
                 The drops to be printed are 
                 Very simple print head fabrica- 
                 Requires very high electrostatic 
                 Silverbrook, EP 0771 658 A2 
               
               
                 pull on ink 
                 selected by some manner (e.g. 
                 tion can be used 
                 field 
                 and related patent applications 
               
               
                   
                 thermally induced surface 
                 The drop selection means does 
                 Electrostatic field for small 
                 Tone-Jet 
               
               
                   
                 tension reduction of pressurized 
                 not need to provide the energy 
                 nozzle sizes is above air break- 
               
               
                   
                 ink). Selected drops are 
                 required to separate the drop 
                 down 
               
               
                   
                 separated from the ink in the 
                 from the nozzle 
                 Electrostatic field may attract 
               
               
                   
                 nozzle by a strong electric field. 
                   
                 dust 
               
               
                 Magnetic pull 
                 The drops to be printed are 
                 Very simple print head fabrica- 
                 Requires magnetic ink 
                 Silverbrook, EP 0771 658 A2 
               
               
                 on ink 
                 selected by some manner (e.g. 
                 tion can be used 
                 Ink colors other than black are 
                 and related patent applications 
               
               
                   
                 thermally induced surface 
                 The drop selection means does 
                 difficult 
               
               
                   
                 tension reduction of pressurized 
                 not need to provide the energy 
                 Requires very high magnetic 
               
               
                   
                 ink). Selected drops are 
                 required to separate the drop 
                 fields 
               
               
                   
                 separated from the ink in the 
                 from the nozzle 
               
               
                   
                 nozzle by a strong magnetic 
               
               
                   
                 field acting on the magnetic ink. 
               
               
                 Shutter 
                 The actuator moves a shutter to 
                 High speed (&gt;50 kHz) operation 
                 Moving parts are required 
                 IJ13, IJ17, IJ21 
               
               
                   
                 block ink flow to the nozzle. 
                 can be achieved due to reduced 
                 Requires ink pressure modulator 
               
               
                   
                 The ink pressure is pulsed at a 
                 refill time 
                 Friction and wear must be 
               
               
                   
                 multiple of the drop ejection 
                 Drop timing can be very 
                 considered 
               
               
                   
                 frequency. 
                 accurate 
                 Stiction is possible 
               
               
                   
                   
                 The actuator energy can be very 
               
               
                   
                   
                 low 
               
               
                 Shuttered grill 
                 The actuator moves a shutter to 
                 Actuators with small travel can 
                 Moving parts are required 
                 IJ08, IJ15, IJ18, IJ19 
               
               
                   
                 block ink flow through a grill to 
                 be used 
                 Requires ink pressure modulator 
               
               
                   
                 the nozzle. The shutter move- 
                 Actuators with small force can 
                 Friction and wear must be 
               
               
                   
                 ment need only be equal to the 
                 be used 
                 considered 
               
               
                   
                 width of the grill holes. 
                 High speed (&gt;50 kHz) operation 
                 Stiction is possible 
               
               
                   
                   
                 can be achieved 
               
               
                 Pulsed mag- 
                 A pulsed magnetic field attracts 
                 Extremely low energy operation 
                 Requires an external pulsed 
                 IJ10 
               
               
                 netic pull on 
                 an ‘ink pusher’ at the drop 
                 is possible 
                 magnetic field 
               
               
                 ink pusher 
                 ejection frequency. An actuator 
                 No heat dissipation problems 
                 Requires special materials for 
               
               
                   
                 controls a catch, which prevents 
                   
                 both the actuator and the ink 
               
               
                   
                 the ink pusher from moving 
                   
                 pusher 
               
               
                   
                 when a drop is not to be ejected. 
                   
                 Complex construction 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
            
               
                   
               
               
                 AUXILIARY MECHANISM (APPLIED TO ALL NOZZLES) 
               
            
           
           
               
               
               
               
               
            
               
                   
                 Description 
                 Advantages 
                 Disadvantages 
                 Examples 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                 None 
                 The actuator directly fires the 
                 Simplicity of construction 
                 Drop ejection energy must be 
                 Most ink jets, including piezo- 
               
               
                   
                 ink drop, and there is no external 
                 Simplicity of operation 
                 supplied by individual nozzle 
                 electric and thermal bubble. 
               
               
                   
                 field or other mechanism 
                 Small physical size 
                 actuator 
                 IJ01, IJ02, IJ03, IJ04, IJ05, IJ07, 
               
               
                   
                 required. 
                   
                   
                 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 ink 
                 The ink pressure oscillates, 
                 Oscillating ink pressure can 
                 Requires external ink pressure 
                 Silverbrook, EP 0771 658 A2 
               
               
                 pressure 
                 providing much of the drop 
                 provide a refill pulse, allowing 
                 oscillator 
                 and related patent applications 
               
               
                 (including 
                 ejection energy. The actuator 
                 higher operating speed 
                 Ink pressure phase and 
                 IJ08, IJ13, IJ15, IJ17, IJ18, IJ19, 
               
               
                 acoustic 
                 selects which drops are to be 
                 The actuators may operate with 
                 amplitude must be carefully 
                 IJ21 
               
               
                 stimulation) 
                 fired by selectively blocking 
                 much lower energy 
                 controlled 
               
               
                   
                 or enabling nozzles. The ink 
                 Acoustic lenses can be used to 
                 Acoustic reflections in the ink 
               
               
                   
                 pressure oscillation may be 
                 focus the sound on the nozzles 
                 chamber must be designed for 
               
               
                   
                 achieved by vibrating the 
               
               
                   
                 print head, or preferably by 
               
               
                   
                 an actuator in the ink supply. 
               
               
                 Media 
                 The print head is placed in close 
                 Low power 
                 Precision assembly required 
                 Silverbrook, EP 0771 658 A2 
               
               
                 proximity 
                 proximity to the print medium. 
                 High accuracy 
                 Paper fibers may cause problems 
                 and related patent applications 
               
               
                   
                 Selected drops protrude from the 
                 Simple print head construction 
                 Cannot print on rough substrates 
               
               
                   
                 print head further than un- 
               
               
                   
                 selected drops, and contact the 
               
               
                   
                 print medium. The drop soaks 
               
               
                   
                 into the medium fast enough to 
               
               
                   
                 cause drop separation. 
               
               
                 Transfer roller 
                 Drops are printed to a transfer 
                 High accuracy 
                 Bulky 
                 Silverbrook, EP 0771 658 A2 
               
               
                   
                 roller instead of straight to the 
                 Wide range of print substrates 
                 Expensive 
                 and related patent applications 
               
               
                   
                 print medium. A transfer roller 
                 can be used 
                 Complex construction 
                 Tektronix hot melt piezoelectric 
               
               
                   
                 can also be used for proximity 
                 Ink can be dried on the transfer 
                   
                 ink jet 
               
               
                   
                 drop separation. 
                 roller 
                   
                 Any of the IJ series 
               
               
                 Electrostatic 
                 An electric field is used to 
                 Low power 
                 Field strength required for 
                 Silverbrook, EP 0771 658 A2 
               
               
                   
                 accelerate selected drops 
                 Simple print head construction 
                 separation of small drops is 
                 and related patent applications 
               
               
                   
                 towards the print medium. 
                   
                 near or above air breakdown 
                 Tone-Jet 
               
               
                 Direct mag- 
                 A magnetic field is used to 
                 Low power 
                 Requires magnetic ink 
                 Silverbrook, EP 0771 658 A2 
               
               
                 netic field 
                 accelerate selected drops of 
                 Simple print head construction 
                 Requires strong magnetic field 
                 and related patent applications 
               
               
                   
                 magnetic ink towards the print 
               
               
                   
                 medium. 
               
               
                 Cross magnetic 
                 The print head is placed in a 
                 Does not require magnetic 
                 Requires external magnet 
                 IJ06, IJ16 
               
               
                 field 
                 constant magnetic field. The 
                 materials to be integrated in the 
                 Current densities may be high, 
               
               
                   
                 Lorenz force in a current 
                 print head manufacturing 
                 resulting in electromigration 
               
               
                   
                 carrying wire is used to move 
                 process 
                 problems 
               
               
                   
                 the actuator. 
               
               
                 Pulsed mag- 
                 A pulsed magnetic field is used 
                 Very low power operation is 
                 Complex print head construction 
                 IJ10 
               
               
                 netic field 
                 to cyclically attract a paddle, 
                 possible 
                 Magnetic materials required in 
               
               
                   
                 which pushes on the ink. A 
                 Small print head size 
                 print head 
               
               
                   
                 small actuator moves a catch, 
               
               
                   
                 which selectively prevents the 
               
               
                   
                 paddle from moving. 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
            
               
                   
               
               
                 ACTUATOR AMPLIFICATION OR MODIFICATION METHOD 
               
            
           
           
               
               
               
               
               
            
               
                   
                 Description 
                 Advantages 
                 Disadvantages 
                 Examples 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                 None 
                 No actuator mechanical ampli- 
                 Operational simplicity 
                 Many actuator mechanisms have 
                 Thermal Bubble Ink jet 
               
               
                   
                 fication is used. The actuator 
                   
                 insufficient travel, or insufficient 
                 IJ01, IJ02, IJ06, IJ07, IJ16, IJ25, 
               
               
                   
                 directly drives the drop ejection 
                   
                 force, to efficiently drive the 
                 IJ26 
               
               
                   
                 process. 
                   
                 drop ejection process 
               
               
                 Differential 
                 An actuator material expands 
                 Provides greater travel in a 
                 High stresses are involved 
                 Piezoelectric 
               
               
                 expansion bend 
                 more on one side than on the 
                 reduced print head area 
                 Care must be taken that the 
                 IJ03, IJ09, IJ17, IJ18, IJ19, IJ20, 
               
               
                 actuator 
                 other. The expansion may be 
                   
                 materials do not delaminate 
                 IJ21, IJ22, IJ23, IJ24, IJ27, IJ29, 
               
               
                   
                 thermal, piezoelectric, magneto- 
                   
                 Residual bend resulting from 
                 IJ30, IJ31, IJ32, IJ33, IJ34, IJ35, 
               
               
                   
                 strictive, or other mechanism. 
                   
                 high temperature or high stress 
                 IJ36, IJ37, IJ38, IJ39, IJ42, IJ43, 
               
               
                   
                 The bend actuator converts a 
                   
                 during formation 
                 IJ44 
               
               
                   
                 high force low travel actuator 
               
               
                   
                 mechanism to high travel, lower 
               
               
                   
                 force mechanism. 
               
               
                 Transient bend 
                 A trilayer bend actuator where 
                 Very good temperature stability 
                 High stresses are involved 
                 IJ40, IJ41 
               
               
                 actuator 
                 the two outside layers are 
                 High speed, as a new drop can 
                 Care must be taken that the 
               
               
                   
                 identical. This cancels bend due 
                 be fired before heat dissipates 
                 materials do not delaminate 
               
               
                   
                 to ambient temperature and 
                 Cancels residual stress of 
               
               
                   
                 residual stress. The actuator only 
                 formation 
               
               
                   
                 responds to transient heating of 
               
               
                   
                 one side or the other. 
               
               
                 Reverse spring 
                 The actuator loads a spring. 
                 Better coupling to the ink 
                 Fabrication complexity 
                 IJ05, IJ11 
               
               
                   
                 When the actuator is turned off, 
                   
                 High stress in the spring 
               
               
                   
                 the spring releases. This can 
               
               
                   
                 reverse the force/distance curve 
               
               
                   
                 of the actuator to make it 
               
               
                   
                 compatible with the force/time 
               
               
                   
                 requirements of the drop 
               
               
                   
                 ejection. 
               
               
                 Actuator stack 
                 A series of thin actuators are 
                 Increased travel 
                 Increased fabrication complexity 
                 Some piezoelectric ink jets 
               
               
                   
                 stacked. This can be appropriate 
                 Reduced drive voltage 
                 Increased possibility of short 
                 IJ04 
               
               
                   
                 where actuators require high 
                   
                 circuits due to pinholes 
               
               
                   
                 electric field strength, such as 
               
               
                   
                 electrostatic and piezoelectric 
               
               
                   
                 actuators. 
               
               
                 Multiple 
                 Multiple smaller actuators are 
                 Increases the force available 
                 Actuator forces may not add 
                 IJ12, IJ13, IJ18, IJ20, IJ22, IJ28, 
               
               
                 actuators 
                 used simultaneously to move the 
                 from an actuator 
                 linearly, reducing efficiency 
                 IJ42, IJ43 
               
               
                   
                 ink. Each actuator need provide 
                 Multiple actuators can be 
               
               
                   
                 only a portion of the force 
                 positioned to control ink flow 
               
               
                   
                 required. 
                 accurately 
               
               
                 Linear Spring 
                 A linear spring is used to trans- 
                 Matches low travel actuator with 
                 Requires print head area for the 
                 IJ15 
               
               
                   
                 form a motion with small travel 
                 higher travel requirements 
                 spring 
               
               
                   
                 and high force into a longer 
                 Non-contact method of motion 
               
               
                   
                 travel, lower force motion. 
                 transformation 
               
               
                 Coiled actuator 
                 A bend actuator is coiled to 
                 Increase travel 
                 Generally restricted to planar 
                 IJ17, IJ21, IJ34, IJ35 
               
               
                   
                 provide greater travel in a 
                 Reduces chip area 
                 implementations due to extreme 
               
               
                   
                 reduced chip area. 
                 Planar implementations are 
                 fabrication difficulty in other 
               
               
                   
                   
                 relatively easy to fabricate. 
                 orientations. 
               
               
                 Flexure bend 
                 A bend actuator has a small 
                 Simple means of increasing 
                 Care must be taken not to 
                 IJ10, IJ19, IJ33 
               
               
                 actuator 
                 region near the fixture point, 
                 travel of a bend actuator 
                 exceed the elastic limit in the 
               
               
                   
                 which flexes much more readily 
                   
                 flexure area 
               
               
                   
                 than the remainder of the 
                   
                 Stress distribution is very 
               
               
                   
                 actuator. The actuator flexing 
                   
                 uneven 
               
               
                   
                 is effectively converted from an 
                   
                 Difficult to accurately model 
               
               
                   
                 even coiling to an angular bend, 
                   
                 with finite element analysis 
               
               
                   
                 resulting in greater travel of 
               
               
                   
                 the actuator tip. 
               
               
                 Catch 
                 The actuator controls a small 
                 Very low actuator energy 
                 Complex construction 
                 IJ10 
               
               
                   
                 catch. The catch either enables 
                 Very small actuator size 
                 Requires external force 
               
               
                   
                 or disables movement of an ink 
                   
                 Unsuitable for pigmented inks 
               
               
                   
                 pusher that is controlled in a 
               
               
                   
                 bulk manner. 
               
               
                 Gears 
                 Gears can be used to increase 
                 Low force, low travel actuators 
                 Moving parts are required 
                 IJ13 
               
               
                   
                 travel at the expense of duration. 
                 can be used 
                 Several actuator cycles are 
               
               
                   
                 Circular gears, rack and pinion, 
                 Can be fabricated using standard 
                 required 
               
               
                   
                 ratchets, and other gearing 
                 surface MEMS processes 
                 More complex drive electronics 
               
               
                   
                 methods can be used. 
                   
                 Complex construction 
               
               
                   
                   
                   
                 Friction, friction, and wear are 
               
               
                   
                   
                   
                 possible 
               
               
                 Buckle plate 
                 A buckle plate can be used to 
                 Very fast movement achievable 
                 Must stay within elastic limits of 
                 S. Hirata et al, “An Ink-jet Head 
               
               
                   
                 change a slow actuator into a 
                   
                 the materials for long device life 
                 Using Diaphragm Micro- 
               
               
                   
                 fast motion. It can also convert 
                   
                 High stresses involved 
                 actuator”, Proc. IEEE MEMS, 
               
               
                   
                 a high force, low travel actuator 
                   
                 Generally high power require- 
                 Feb. 1996, pp 418-423. 
               
               
                   
                 into a high travel, medium force 
                   
                 ment 
                 IJ18, IJ27 
               
               
                   
                 motion. 
               
               
                 Tapered mag- 
                 A tapered magnetic pole can 
                 Linearizes the magnetic force/ 
                 Complex construction 
                 IJ14 
               
               
                 netic pole 
                 increase travel at the expense 
                 distance curve 
               
               
                   
                 of force. 
               
               
                 Lever 
                 A lever and fulcrum is used to 
                 Matches low travel actuator with 
                 High stress around the fulcrum 
                 IJ32, IJ36, IJ37 
               
               
                   
                 transform a motion with small 
                 higher travel requirements 
               
               
                   
                 travel and high force into a 
                 Fulcrum area has no linear 
               
               
                   
                 motion with longer travel and 
                 movement, and can be used for a 
               
               
                   
                 lower force. The lever can also 
                 fluid seal 
               
               
                   
                 reverse the direction of travel. 
               
               
                 Rotary impeller 
                 The actuator is connected to a 
                 High mechanical advantage 
                 Complex construction 
                 IJ28 
               
               
                   
                 rotary impeller. A small angular 
                 The ratio of force to travel of 
                 Unsuitable for pigmented inks 
               
               
                   
                 deflection of the actuator results 
                 the actuator can be matched to 
               
               
                   
                 in a rotation of the impeller 
                 the nozzle requirements by 
               
               
                   
                 vanes, which push the ink 
                 varying the number of impeller 
               
               
                   
                 against stationary vanes and out 
                 vanes 
               
               
                   
                 of the nozzle. 
               
               
                 Acoustic lens 
                 A refractive or diffractive (e.g. 
                 No moving parts 
                 Large area required 
                 1993 Hadimioglu et al, EUP 
               
               
                   
                 zone plate) acoustic lens is used 
                   
                 Only relevant for acoustic ink 
                 550,192 
               
               
                   
                 to concentrate sound waves. 
                   
                 jets 
                 1993 Elrod et al, EUP 572,220 
               
               
                 Sharp con- 
                 A sharp point is used to concen- 
                 Simple construction 
                 Difficult to fabricate using 
                 Tone-jet 
               
               
                 ductive point 
                 trate an electrostatic field. 
                   
                 standard VLSI processes for a 
               
               
                   
                   
                   
                 surface ejecting ink-jet 
               
               
                   
                   
                   
                 Only relevent for electrostatic 
               
               
                   
                   
                   
                 ink jets 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
            
               
                   
               
               
                 ACTUATOR MOTION 
               
            
           
           
               
               
               
               
               
            
               
                   
                 Description 
                 Advantages 
                 Disadvantages 
                 Examples 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                 Volume 
                 The volume of the actuator 
                 Simple construction in the case 
                 High energy is typically required 
                 Hewlett-Packard Thermal Ink jet 
               
               
                 expansion 
                 changes, pushing the ink in all 
                 of thermal ink jet 
                 to achieve volume expansion. 
                 Canon Bubblejet 
               
               
                   
                 directions. 
                   
                 This leads to thermal stress, 
               
               
                   
                   
                   
                 cavitation, and kogation in 
               
               
                   
                   
                   
                 thermal ink jet implementations 
               
               
                 Linear, normal 
                 The actuator moves in a 
                 Efficient coupling to ink drops 
                 High fabrication complexity may 
                 IJ01, IJ02, IJ04, IJ07, IJ11, IJ14 
               
               
                 to chip surface 
                 direction normal to the print 
                 ejected normal to the surface 
                 be required to achieve per- 
               
               
                   
                 head surface. The nozzle is 
                   
                 pendicular motion 
               
               
                   
                 typically in the line of 
               
               
                   
                 movement. 
               
               
                 Parallel to 
                 The actuator moves parallel to 
                 Suitable for planar fabrication 
                 Fabrication complexity 
                 IJ12, IJ13, IJ15, IJ33, IJ34, IJ35, 
               
               
                 chip surface 
                 the print head surface. Drop 
                   
                 Friction 
                 IJ36 
               
               
                   
                 ejection may still be normal to 
                   
                 Stiction 
               
               
                   
                 the surface. 
               
               
                 Membrane 
                 An actuator with a high force 
                 The effective area of the actuator 
                 Fabrication complexity 
                 1982 Howkins U.S. Pat. No. 
               
               
                 push 
                 but small area is used to push a 
                 becomes the membrane area 
                 Actuator size 
                 4,459,601 
               
               
                   
                 stiff membrane that is in contact 
                   
                 Difficulty of integration in a 
               
               
                   
                 with the ink. 
                   
                 VLSI process 
               
               
                 Rotary 
                 The actuator causes the rotation 
                 Rotary levers may be used to 
                 Device complexity 
                 IJ05, IJ08, IJ13, IJ28 
               
               
                   
                 of some element, such a grill or 
                 increase travel 
                 May have friction at a pivot 
               
               
                   
                 impeller 
                 Small chip area requirements 
                 point 
               
               
                 Bend 
                 The actuator bends when 
                 A very small change in 
                 Requires the actuator to be made 
                 1970 Kyser et al U.S. Pat. No. 
               
               
                   
                 energized. This may be due to 
                 dimensions can be converted to 
                 from at least two distinct layers, 
                 3,946,398 
               
               
                   
                 differential thermal expansion, 
                 a large motion. 
                 or to have a thermal difference 
                 1973 Stemme U.S. Pat. No. 
               
               
                   
                 piezoelectric expansion, mag- 
                   
                 across the actuator 
                 3,747,120 
               
               
                   
                 netostriction, or other form of 
                   
                   
                 IJ03, IJ09, IJ10, IJ19, IJ23, IJ24, 
               
               
                   
                 relative dimensional change. 
                   
                   
                 IJ25, IJ29, IJ30, IJ31, IJ33, IJ34, 
               
               
                   
                   
                   
                   
                 IJ35 
               
               
                 Swivel 
                 The actuator swivels around a 
                 Allows operation where the net 
                 Inefficient coupling to the ink 
                 IJ06 
               
               
                   
                 central pivot. This motion is 
                 linear force on the paddle is zero 
                 motion 
               
               
                   
                 suitable where there are opposite 
                 Small chip area requirements 
               
               
                   
                 forces applied to opposite sides 
               
               
                   
                 of the paddle, e.g. Lorenz force. 
               
               
                 Straighten 
                 The actuator is normally bent, 
                 Can be used with shape memory 
                 Requires careful balance of 
                 IJ26, IJ32 
               
               
                   
                 and straightens when energized. 
                 alloys where the austenic phase 
                 stresses to ensure that the 
               
               
                   
                   
                 is planar 
                 quiescent bend is accurate 
               
               
                 Double bend 
                 The actuator bends in one 
                 One actuator can be used to 
                 Difficult to make the drops 
                 IJ36, IJ37, IJ38 
               
               
                   
                 direction when one element is 
                 power two nozzles. 
                 ejected by both bend directions 
               
               
                   
                 energized, and bends the other 
                 Reduced chip size. 
                 identical. 
               
               
                   
                 way when another element is 
                 Not sensitive to ambient 
                 A small efficiency loss 
               
               
                   
                 energized. 
                 temperature 
                 compared to equivalent single 
               
               
                   
                   
                   
                 bend actuators. 
               
               
                 Shear 
                 Energizing the actuator causes a 
                 Can increase the effective travel 
                 Not readily applicable to other 
                 1985 Fishbeck U.S. Pat. No. 
               
               
                   
                 shear motion in the actuator 
                 of piezoelectric actuators 
                 actuator mechanisms 
                 4,584,590 
               
               
                   
                 material. 
               
               
                 Radial con- 
                 The actuator squeezes an ink 
                 Relatively easy to fabricate 
                 High force required 
                 1970 Zoltan U.S. Pat. No. 
               
               
                 striction 
                 reservoir, forcing ink from a 
                 single nozzles from glass tubing 
                 Inefficient 
                 3,683,212 
               
               
                   
                 constricted nozzle. 
                 as macroscopic structures 
                 Difficult to integrate with VLSI 
               
               
                   
                   
                   
                 processes 
               
               
                 Coil/uncoil 
                 A coiled actuator uncoils or coils 
                 Easy to fabricate as a planar 
                 Difficult to fabricate for non- 
                 IJ17, IJ21, IJ34, IJ35 
               
               
                   
                 more tightly. The motion of the 
                 VLSI process 
                 planar devices 
               
               
                   
                 free end of the actuator ejects 
                 Small area required, therefore 
                 Poor out-of-plane stiffness 
               
               
                   
                 the ink. 
                 low cost 
               
               
                 Bow 
                 The actuator bows (or buckles) 
                 Can increase the speed of travel 
                 Maximum travel is constrained 
                 IJ16, IJ18, IJ27 
               
               
                   
                 in the middle when energized. 
                 Mechanically rigid 
                 High force required 
               
               
                 Push-Pull 
                 Two actuators control a shutter. 
                 The structure is pinned at both 
                 Not readily suitable for ink jets 
                 IJ18 
               
               
                   
                 One actuator pulls the shutter, 
                 ends, so has a high out-of-plane 
                 which directly push the ink 
               
               
                   
                 and the other pushes it. 
                 rigidity 
               
               
                 Curl inwards 
                 A set of actuators curl inwards 
                 Good fluid flow to the region 
                 Design complexity 
                 IJ20, IJ42 
               
               
                   
                 to reduce the volume of ink that 
                 behind the actuator increases 
               
               
                   
                 they enclose. 
                 efficiency 
               
               
                 Curl outwards 
                 A set of actuators curl outwards, 
                 Relatively simple construction 
                 Relatively large chip area 
                 IJ43 
               
               
                   
                 pressurizing ink in a chamber 
               
               
                   
                 surrounding the actuators, and 
               
               
                   
                 expelling ink from a nozzle in 
               
               
                   
                 the chamber. 
               
               
                 Iris 
                 Multiple vanes enclose a volume 
                 High efficiency 
                 High fabrication complexity 
                 IJ22 
               
               
                   
                 of ink. These simultaneously 
                 Small chip area 
                 Not suitable for pigmented inks 
               
               
                   
                 rotate, reducing the volume 
               
               
                   
                 between the vanes. 
               
               
                 Acoustic 
                 The actuator vibrates at a high 
                 The actuator can be physically 
                 Large area required for efficient 
                 1993 Hadimioglu et al, EUP 
               
               
                 vibration 
                 frequency. 
                 distant from the ink 
                 operation at useful frequencies 
                 550,192 
               
               
                   
                   
                   
                 Acoustic coupling and crosstalk 
                 1993 Elrod et al, EUP 572,220 
               
               
                   
                   
                   
                 Complex drive circuitry 
               
               
                   
                   
                   
                 Poor control drop volume and 
               
               
                   
                   
                   
                 position 
               
               
                 None 
                 In various ink jet designs the 
                 No moving parts 
                 Various other tradeoffs are 
                 Silverbrook, EP 0771 658 A2 
               
               
                   
                 actuator does not move. 
                   
                 required to eliminate moving 
                 and related patent applications 
               
               
                   
                   
                   
                 parts 
                 Tone-jet 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
            
               
                   
               
               
                 NOZZLE REFILL METHOD 
               
            
           
           
               
               
               
               
               
            
               
                   
                 Description 
                 Advantages 
                 Disadvantages 
                 Examples 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                 Surface tension 
                 This is the normal way that ink 
                 Fabrication simplicity 
                 Low speed 
                 Thermal ink jet 
               
               
                   
                 jets are refilled. After the 
                 Operational simplicity 
                 Surface tension force relatively 
                 Piezoelectric ink jet 
               
               
                   
                 actuator is energized, it 
                   
                 small compared to actuator force 
                 IJ01-IJ07, IJ10-IJ14, IJ16, IJ20, 
               
               
                   
                 typically returns rapidly to its 
                   
                 Long refill time usually 
                 IJ22-IJ45 
               
               
                   
                 normal position. This rapid 
                   
                 dominates the total repetition 
               
               
                   
                 return sucks in air through the 
                   
                 rate 
               
               
                   
                 nozzle 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 chamber is 
                 High speed 
                 Requires common ink pressure 
                 IJ08, IJ13, IJ15, IJ17, IJ18, IJ19, 
               
               
                 oscillating 
                 provided at a pressure that 
                 Low actuator energy, as the 
                 oscillator 
                 IJ21 
               
               
                 ink pressure 
                 oscillates at twice the drop 
                 actuator need only open or close 
                 May not be suitable for pig- 
               
               
                   
                 ejection frequency. When a drop 
                 the shutter, instead of ejecting 
                 mented inks 
               
               
                   
                 is to be ejected, the shutter is 
                 the ink drop 
               
               
                   
                 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 actuator 
                 After the main actuator has 
                 High speed, as the nozzle is 
                 Requires two independent 
                 IJ09 
               
               
                   
                 ejected a 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 pre- 
               
               
                   
                 vent its return from emptying the 
               
               
                   
                 chamber again. 
               
               
                 Positive ink 
                 The ink is held a slight positive 
                 High refill rate, therefore a high 
                 Surface spill must be prevented 
                 Silverbrook, EP 0771 658 A2 
               
               
                 pressure 
                 pressure. After the ink drop is 
                 drop repetition rate is possible 
                 Highly hydrophobic print head 
                 and related patent applications 
               
               
                   
                 ejected, the nozzle chamber fills 
                   
                 surfaces are required 
                 Alternative for: IJ01-IJ07, 
               
               
                   
                 quickly as surface tension and 
                   
                   
                 IJ10-IJ14, IJ16, IJ20, IJ22-IJ45 
               
               
                   
                 ink pressure both operate to 
               
               
                   
                 refill the nozzle. 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
            
               
                   
               
               
                 METHOD OF RESTRICTING BACK-FLOW THROUGH INLET 
               
            
           
           
               
               
               
               
               
            
               
                   
                 Description 
                 Advantages 
                 Disadvantages 
                 Examples 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                 Long inlet 
                 The ink inlet channel to the 
                 Design simplicity 
                 Restricts refill rate 
                 Thermal ink jet 
               
               
                 channel 
                 nozzle chamber is made long 
                 Operational simplicity 
                 May result in a relatively large 
                 Piezoelectric ink jet 
               
               
                   
                 and relatively narrow, relying on 
                 Reduces crosstalk 
                 chip area 
                 IJ42, IJ43 
               
               
                   
                 viscous drag to reduce inlet 
                   
                 Only partially effective 
               
               
                   
                 back-flow. 
               
               
                 Positive ink 
                 The ink is under a positive 
                 Drop selection and separation 
                 Requires a method (such as a 
                 Silverbrook, EP 0771 658 A2 
               
               
                 pressure 
                 pressure, so that in the 
                 forces can be reduced 
                 nozzle rim or effective hydro- 
                 and related patent applications 
               
               
                   
                 quiescent state some of the ink 
                 Fast refill time 
                 phobizing, or both) to prevent 
                 Possible operation of the 
               
               
                   
                 drop already protrudes from the 
                   
                 flooding of the ejection 
                 following: IJ01-IJ07, IJ09-IJ12, 
               
               
                   
                 nozzle. This reduces the pressure 
                   
                 surface of the print head. 
                 IJ14, IJ16, IJ20, IJ22, IJ23- 
               
               
                   
                 in the nozzle chamber which is 
                   
                   
                 IJ34, IJ36-IJ41, IJ44 
               
               
                   
                 required to eject a certain 
               
               
                   
                 volume of ink. The reduction in 
               
               
                   
                 chamber pressure results in a 
               
               
                   
                 reduction in ink pushed out 
               
               
                   
                 through the inlet. 
               
               
                 Baffle 
                 One or more baffles are placed 
                 The refill rate is not as restricted 
                 Design complexity 
                 HP Thermal Ink Jet 
               
               
                   
                 in the inlet ink flow. When the 
                 as the long inlet method. 
                 May increase fabrication 
                 Tektronix piezoelectric ink jet 
               
               
                   
                 actuator is energized, the rapid 
                 Reduces crosstalk 
                 complexity (e.g. Tektronix hot 
               
               
                   
                 ink movement creates eddies 
                   
                 melt Piezoelectric print heads). 
               
               
                   
                 which restrict the flow through 
               
               
                   
                 the inlet. The slower refill 
               
               
                   
                 process is unrestricted, and does 
               
               
                   
                 not result in eddies. 
               
               
                 Flexible flap 
                 In this method recently disclosed 
                 Significantly reduces back-flow 
                 Not applicable to most ink jet 
                 Canon 
               
               
                 restricts inlet 
                 by Canon, the expanding 
                 for edge-shooter thermal ink jet 
                 configurations 
               
               
                   
                 actuator (bubble) pushes on a 
                 devices 
                 Increased fabrication complexity 
               
               
                   
                 flexible flap that resticts the 
                   
                 Inelastic deformation of polymer 
               
               
                   
                 inlet. 
                   
                 flap results in creep over 
               
               
                   
                   
                   
                 extended use 
               
               
                 Inlet filter 
                 A filter is located between the 
                 Additional advantage of ink fil- 
                 Restricts refill rate 
                 IJ04, IJ12, IJ24, IJ27, IJ29, IJ30 
               
               
                   
                 ink inlet and the nozzle 
                 tration 
                 May result in complex con- 
               
               
                   
                 chamber. The filter has a multi- 
                 Ink filter may be fabricated with 
                 struction 
               
               
                   
                 tude of small holes or slots, 
                 no additional process steps 
               
               
                   
                 restricting ink flow. The filter 
               
               
                   
                 also removes particles which 
               
               
                   
                 may block the nozzle. 
               
               
                 Small inlet 
                 The ink inlet channel to the 
                 Design simplicity 
                 Restricts refill rate 
                 IJ02, IJ37, IJ44 
               
               
                 compared to 
                 nozzle chamber has a sub- 
                   
                 May result in a relatively large 
               
               
                 nozzle 
                 stantially smaller cross section 
                   
                 chip area 
               
               
                   
                 than that of the nozzle, resulting 
                   
                 Only partially effective 
               
               
                   
                 in easier ink egress out of the 
               
               
                   
                 nozzle than out of the inlet. 
               
               
                 Inlet shutter 
                 A secondary actuator controls 
                 Increases speed of the ink-jet 
                 Requires separate refill actuator 
                 IJ09 
               
               
                   
                 the position of a shutter, closing 
                 print head operation 
                 and drive circuit 
               
               
                   
                 off the ink inlet when the main 
               
               
                   
                 actuator is energized. 
               
               
                 The inlet is 
                 The method avoids the problem 
                 Back-flow problem is eliminated 
                 Requires careful design to 
                 IJ01, IJ03, IJ05, IJ06, IJ07, IJ10, 
               
               
                 located behind 
                 of inlet back-flow by arranging 
                   
                 minimize the negative pressure 
                 IJ11, IJ14, IJ16, IJ22, IJ23, IJ25, 
               
               
                 the ink-pushing 
                 the ink-pushing surface of the 
                   
                 behind the paddle 
                 IJ28, IJ31, IJ32, IJ33, IJ34, IJ35, 
               
               
                 surface 
                 actuator between the inlet and 
                   
                   
                 IJ36, IJ39, IJ40, IJ41 
               
               
                   
                 the nozzle. 
               
               
                 Part of the 
                 The actuator and a wall of the 
                 Significant reductions in back- 
                 Small increases in fabrication 
                 IJ07, IJ20, IJ26, IJ38 
               
               
                 actuator moves 
                 ink chamber are arranged so that 
                 flow can be achieved 
                 complexity 
               
               
                 to shut off the 
                 the motion of the actuator 
                 Compact designs possible 
               
               
                 inlet 
                 closes off the inlet. 
               
               
                 Nozzle actuator 
                 In some configurations of ink 
                 Ink back-flow problem is 
                 None related to ink back-flow on 
                 Silverbrook, EP 0771 658 A2 
               
               
                 does not result 
                 jet, there is no expansion or 
                 eliminated 
                 actuation 
                 and related patent applications 
               
               
                 in ink back- 
                 movement of an actuator which 
                   
                   
                 Valve-jet 
               
               
                 flow 
                 may cause ink back-flow 
                   
                   
                 Tone-jet 
               
               
                   
                 through the inlet. 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
            
               
                   
               
               
                 NOZZLE CLEARING METHOD 
               
            
           
           
               
               
               
               
               
            
               
                   
                 Description 
                 Advantages 
                 Disadvantages 
                 Examples 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                 Normal nozzle 
                 All of the nozzles are fired 
                 No added complexity on the 
                 May not be sufficient to 
                 Most ink jet systems 
               
               
                 firing 
                 periodically, before the ink has 
                 print head 
                 displace dried ink 
                 IJ01, IJ02, IJ03, IJ04, IJ05, IJ06, 
               
               
                   
                 a chance to dry. When not in use 
                   
                   
                 IJ07, IJ09, IJ10, IJ11, IJ12, IJ14, 
               
               
                   
                 the nozzles are sealed (capped) 
                   
                   
                 IJ16, IJ20, IJ22, IJ23, IJ24, IJ25, 
               
               
                   
                 against air. The nozzle firing is 
                   
                   
                 IJ26, IJ27, IJ28, IJ29, IJ30, IJ31, 
               
               
                   
                 usually performed during a 
                   
                   
                 IJ32, IJ33, IJ34, IJ36, IJ37, IJ38, 
               
               
                   
                 special clearing cycle, after first 
                   
                   
                 IJ39, IJ40, IJ41, IJ42, IJ43, IJ44, 
               
               
                   
                 moving the print head to a 
                   
                   
                 IJ45 
               
               
                   
                 cleaning station. 
               
               
                 Extra power 
                 In systems which heat the ink, 
                 Can be highly effective if the 
                 Requires higher drive voltage for 
                 Silverbrook, EP 0771 658 A2 
               
               
                 to ink heater 
                 but do not boil it under normal 
                 heater is adjacent to the nozzle 
                 clearing 
                 and related patent applications 
               
               
                   
                 situations, nozzle clearing can 
                   
                 May require larger drive 
               
               
                   
                 be achieved by over-powering 
                   
                 transistors 
               
               
                   
                 the heater and boiling ink at the 
               
               
                   
                 nozzle. 
               
               
                 Rapid success- 
                 The actuator is fired in rapid 
                 Does not require extra drive 
                 Effectiveness depends sub- 
                 May be used with: IJ01, IJ02, 
               
               
                 ion of actuator 
                 succession. In some configura- 
                 circuits on the print head 
                 stantially upon the configuration 
                 IJ03, IJ04, IJ05, IJ06, IJ07, IJ09, 
               
               
                 pulses 
                 tions, this may cause heat build- 
                 Can be readily controlled and 
                 of the ink jet nozzle 
                 IJ10, IJ11, IJ14, IJ16, IJ20, IJ22, 
               
               
                   
                 up at the nozzle which boils the 
                 initiated by digital logic 
                   
                 IJ23, IJ24, IJ25, IJ27, IJ28, IJ29, 
               
               
                   
                 ink, clearing the nozzle. In other 
                   
                   
                 IJ30, IJ31, IJ32, IJ33, IJ34, IJ36, 
               
               
                   
                 situations, it may cause 
                   
                   
                 IJ37, IJ38, IJ39, IJ40, IJ41, IJ42, 
               
               
                   
                 sufficient vibrations to dislodge 
                   
                   
                 IJ43, IJ44, IJ45 
               
               
                   
                 clogged nozzles. 
               
               
                 Extra power to 
                 Where an actuator is not 
                 A simple solution where 
                 Not suitable where there is a 
                 May be used with: IJ03, IJ09, 
               
               
                 ink pushing 
                 normally driven to the limit of 
                 applicable 
                 hard limit to actuator movement 
                 IJ16, IJ20, IJ23, IJ24, IJ25, IJ27, 
               
               
                 actuator 
                 its motion, nozzle clearing may 
                   
                   
                 IJ29, IJ30, IJ31, IJ32, IJ39, IJ40, 
               
               
                   
                 be assisted by providing an 
                   
                   
                 IJ41, IJ42, IJ43, IJ44, IJ45 
               
               
                   
                 enhanced drive signal to the 
               
               
                   
                 actuator. 
               
               
                 Acoustic 
                 An ultrasonic wave is applied to 
                 A high nozzle clearing capability 
                 High implementation cost if 
                 IJ08, IJ13, IJ15, IJ17, IJ18, IJ19, 
               
               
                 resonance 
                 the ink chamber. This wave is of 
                 can be achieved 
                 system does not already include 
                 IJ21 
               
               
                   
                 an appropriate amplitude and 
                 May be implemented at very low 
                 an acoustic actuator 
               
               
                   
                 frequency to cause sufficient 
                 cost in systems which already 
               
               
                   
                 force at the nozzle to clear 
                 include acoustic actuators 
               
               
                   
                 blockages. This is easiest to 
               
               
                   
                 achieve if the ultrasonic wave is 
               
               
                   
                 at a resonant frequency of the 
               
               
                   
                 ink cavity. 
               
               
                 Nozzle clearing 
                 A microfabricated plate is 
                 Can clear severely clogged 
                 Accurate mechanical alignment 
                 Silverbrook, EP 0771 658 A2 
               
               
                 plate 
                 pushed against the nozzles. The 
                 nozzles 
                 is required 
                 and related patent applications 
               
               
                   
                 plate has a post for every nozzle. 
                   
                 Moving parts are required 
               
               
                   
                 A post moves through each 
                   
                 There is risk of damage to the 
               
               
                   
                 nozzle, displacing dried ink. 
                   
                 nozzles 
               
               
                   
                   
                   
                 Accurate fabrication is required 
               
               
                 Ink pressure 
                 The pressure of the ink is 
                 May be effective where other 
                 Requires pressure pump or other 
                 May be used with all IJ series 
               
               
                 pulse 
                 temporarily increased so that 
                 methods cannot be used 
                 pressure actuator 
                 ink jets 
               
               
                   
                 ink streams from all of the 
                   
                 Expensive 
               
               
                   
                 nozzles. This may be used in 
                   
                 Wasteful of ink 
               
               
                   
                 conjunction with actuator 
               
               
                   
                 energizing. 
               
               
                 Print head 
                 A flexible ‘blade’ is wiped 
                 Effective for planar print head 
                 Difficult to use if print head 
                 Many ink jet systems 
               
               
                 wiper 
                 across the print head surface. 
                 surfaces 
                 surface is non-planar or very 
               
               
                   
                 The blade is usually fabricated 
                 Low cost 
                 fragile 
               
               
                   
                 from a flexible polymer, e.g. 
                   
                 Requires mechanical parts 
               
               
                   
                 rubber or synthetic elastomer. 
                   
                 Blade can wear out in high 
               
               
                   
                   
                   
                 volume print systems 
               
               
                 Separate ink 
                 A separate heater is provided at 
                 Can be effective where other 
                 Fabrication complexity 
                 Can be used with many IJ series 
               
               
                 boiling heater 
                 the nozzle although the normal 
                 nozzle clearing methods cannot 
                   
                 ink jets 
               
               
                   
                 drop e-ection mechanism does 
                 be used 
               
               
                   
                 not require it. The heaters do not 
                 Can be implemented at no 
               
               
                   
                 require individual drive circuits, 
                 additional cost in some ink jet 
               
               
                   
                 as many nozzles can be cleared 
                 configurations 
               
               
                   
                 simultaneously, and no imaging 
               
               
                   
                 is required. 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
            
               
                   
               
               
                 NOZZLE PLATE CONSTRUCTION 
               
            
           
           
               
               
               
               
               
            
               
                   
                 Description 
                 Advantages 
                 Disadvantages 
                 Examples 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                 Electroformed 
                 A nozzle plate is separately 
                 Fabrication simplicity 
                 High temperatures and pressures 
                 Hewlett Packard Thermal Ink jet 
               
               
                 nickel 
                 fabricated from electroformed 
                   
                 are required to bond nozzle plate 
               
               
                   
                 nickel, and bonded to the print 
                   
                 Minimum thickness constraints 
               
               
                   
                 head chip. 
                   
                 Differential thermal expansion 
               
               
                 Laser ablated 
                 Individual nozzle holes are 
                 No mask required 
                 Each hole must be individually 
                 Canon Bubblejet 
               
               
                 or drilled 
                 ablated by an intense UV laser 
                 Can be quite fast 
                 formed 
                 1988 Sercel et al., SPIE, Vol. 
               
               
                 polymer 
                 in a nozzle plate, which is 
                 Some control over nozzle profile 
                 Special equipment required 
                 998 Excimer Beam Applica- 
               
               
                   
                 typically a polymer such as 
                 is possible 
                 Slow where there are many 
                 tions, pp. 76-83 
               
               
                   
                 polyimide or polysulphone 
                 Equipment required is relatively 
                 thousands of nozzles per print 
                 1993 Watanabe et al., U.S. Pat. 
               
               
                   
                   
                 low cost 
                 head 
                 No. 5,208,604 
               
               
                   
                   
                   
                 May produce thin burrs at exit 
               
               
                   
                   
                   
                 holes 
               
               
                 Silicon micro- 
                 A separate nozzle plate is micro- 
                 High accuracy is attainable 
                 Two part construction 
                 K. Bean, IEEE Transactions on 
               
               
                 machined 
                 machined from single crystal 
                   
                 High cost 
                 Electron Devices, Vol. ED-25, 
               
               
                   
                 silicon, and bonded to the print 
                   
                 Requires precision alignment 
                 No. 10, 1978, pp 1185-1195 
               
               
                   
                 head wafer. 
                   
                 Nozzles may be clogged by 
                 Xerox 1990 Hawkins et al., U.S. 
               
               
                   
                   
                   
                 adhesive 
                 Pat. No. 4,899,181 
               
               
                 Glass 
                 Fine glass capillaries are drawn 
                 No expensive equipment 
                 Very small nozzle sizes are 
                 1970 Zoltan U.S. Pat. No. 
               
               
                 capillaries 
                 from glass tubing. This method 
                 required 
                 difficult to form 
                 3,683,212 
               
               
                   
                 has been used for making 
                 Simple to make single nozzles 
                 Not suited for mass production 
               
               
                   
                 individual nozzles, but is 
               
               
                   
                 difficult to use for bulk 
               
               
                   
                 manufacturing of print heads 
               
               
                   
                 with thousands of nozzles. 
               
               
                 Monolithic, 
                 The nozzle plate is deposited as 
                 High accuracy (&lt;1 μm) 
                 Requires sacrificial layer under 
                 Silverbrook, EP 0771 658 A2 
               
               
                 surface micro- 
                 a layer using standard VLSI 
                 Monolithic 
                 the nozzle plate to form the 
                 and related patent applications 
               
               
                 machined using 
                 deposition techniques. Nozzles 
                 Low cost 
                 nozzle chamber 
                 IJ01, IJ02, IJ04, IJ11, IJ12, IJ17, 
               
               
                 VLSI litho- 
                 are etched in the nozzle plate 
                 Existing processes can be used 
                 Surface may be fragile to the 
                 IJ18, IJ20, IJ22, IJ24, IJ27, IJ28, 
               
               
                 graphic pro- 
                 using VLSI lithography and 
                   
                 touch 
                 IJ29, IJ30, IJ31, IJ32, IJ33, IJ34, 
               
               
                 cesses 
                 etching. 
                   
                   
                 IJ36, IJ37, IJ38, IJ39, IJ40, IJ41, 
               
               
                   
                   
                   
                   
                 IJ42, IJ43, IJ44 
               
               
                 Monolithic, 
                 The nozzle plate is a buried etch 
                 High accuracy (&lt;1 μm) 
                 Requires long etch times 
                 IJ03, IJ05, IJ06, IJ07, IJ08, IJ09, 
               
               
                 etched through 
                 stop in the wafer. Nozzle 
                 Monolithic 
                 Requires a support wafer 
                 IJ10, IJ13, IJ14, IJ15, IJ16, IJ19, 
               
               
                 substrate 
                 chambers are etched in the front 
                 Low cost 
                   
                 IJ21, IJ23, IJ25, IJ26 
               
               
                   
                 of the wafer, and the wafer is 
                 No differential expansion 
               
               
                   
                 thinned from the back side. 
               
               
                   
                 Nozzles are then etched in the 
               
               
                   
                 etch stop layer. 
               
               
                 No nozzle plate 
                 Various methods have been tried 
                 No nozzles to become clogged 
                 Difficult to control drop position 
                 Ricoh 1995 Sekiya et al U.S. 
               
               
                   
                 to eliminate the nozzles entirely, 
                   
                 accurately 
                 Pat. No. 5,412,413 
               
               
                   
                 to prevent nozzle clogging. 
                   
                 Crosstalk problems 
                 1993 Hadimioglu et al EUP 
               
               
                   
                 These include thermal bubble 
                   
                   
                 550,192 
               
               
                   
                 mechanisms and acoustic lens 
                   
                   
                 1993 Elrod et al EUP 572,220 
               
               
                   
                 mechanisms 
               
               
                 Trough 
                 Each drop ejector has a trough 
                 Reduced manufacturing 
                 Drop firing direction is sensitive 
                 IJ35 
               
               
                   
                 through which a paddle moves. 
                 complexity 
                 to wicking. 
               
               
                   
                 There is no nozzle plate. 
                 Monolithic 
               
               
                 Nozzle slit 
                 The elimination of nozzle holes 
                 No nozzles to become clogged 
                 Difficult to control drop position 
                 1989 Saito et al U.S. Pat. No. 
               
               
                 instead of 
                 and replacement by a slit 
                   
                 accurately 
                 4,799,068 
               
               
                 individual 
                 encompassing many actuator 
                   
                 Crosstalk problems 
               
               
                 nozzles 
                 positions reduces nozzle 
               
               
                   
                 clogging, but increases crosstalk 
               
               
                   
                 due to ink surface waves 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
            
               
                   
               
               
                 DROP EJECTION DIRECTION 
               
            
           
           
               
               
               
               
               
            
               
                   
                 Description 
                 Advantages 
                 Disadvantages 
                 Examples 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                 Edge (‘edge 
                 Ink flow is along the surface of 
                 Simple construction 
                 Nozzles limited to edge 
                 Canon Bubblejet 1979 Endo et 
               
               
                 shooter’) 
                 the chip, and ink drops are 
                 No silicon etching required 
                 High resolution is difficult 
                 al GB patent 2,007,162 
               
               
                   
                 ejected from the chip edge. 
                 Good heat sinking via substrate 
                 Fast color printing requires one 
                 Xerox heater-in-pit 1990 
               
               
                   
                   
                 Mechanically strong 
                 print head per color 
                 Hawkins et al U.S. Pat. No. 
               
               
                   
                   
                 Ease of chip handing 
                   
                 4,899,181 
               
               
                   
                   
                   
                   
                 Tone-jet 
               
               
                 Surface (‘roof 
                 Ink flow is along the surface of 
                 No bulk silicon etching required 
                 Maximum ink flow is severely 
                 Hewlett-Packard TIJ 1982 
               
               
                 shooter’) 
                 the chip, and ink drops are 
                 Silicon can make an effective 
                 restricted 
                 Vaught et al U.S. Pat. No. 
               
               
                   
                 ejected from the chip surface, 
                 heat sink 
                   
                 4,490,728 
               
               
                   
                 normal to the plane of the chip. 
                 Mechanical strength 
                   
                 IJ02, IJ11, IJ12, IJ20, IJ22 
               
               
                 Through chip, 
                 Ink flow is through the chip, and 
                 High ink flow 
                 Requires bulk silicon etching 
                 Silverbrook, EP 0771 658 A2 
               
               
                 forward (‘up 
                 ink drops are ejected from the 
                 Suitable for pagewidth print 
                   
                 and related patent applications 
               
               
                 shooter’) 
                 front surface of the chip. 
                 heads 
                   
                 IJ04, IJ17, IJ18, IJ24, IJ27-IJ45 
               
               
                   
                   
                 High nozzle packing density 
               
               
                   
                   
                 therefore low manufacturing cost 
               
               
                 Through chip, 
                 Ink flow is through the chip, and 
                 High ink flow 
                 Requires wafer thinning 
                 IJ01, IJ03, IJ05, IJ06, IJ07, IJ08, 
               
               
                 reverse (‘down 
                 ink drops are ejected from the 
                 Suitable for pagewidth print 
                 Requires special handling during 
                 IJ09, IJ10, IJ13, IJ14, IJ15, IJ16, 
               
               
                 shooter’) 
                 rear surface of the chip. 
                 heads 
                 manufacture 
                 IJ19, IJ21, IJ23, IJ25, IJ26 
               
               
                   
                   
                 High nozzle packing density 
               
               
                   
                   
                 therefore low manufacturing cost 
               
               
                 Through 
                 Ink flow is through the actuator, 
                 Suitable for piezoelectric print 
                 Pagewidth print heads require 
                 Epson Stylus 
               
               
                 actuator 
                 which is not fabricated as part of 
                 heads 
                 several thousand connections to 
                 Tektronix hot melt piezoelectric 
               
               
                   
                 the same substrate as the drive 
                   
                 drive circuits 
                 ink jets 
               
               
                   
                 transistors. 
                   
                 Cannot be manufactured in 
               
               
                   
                   
                   
                 standard CMOS fabs 
               
               
                   
                   
                   
                 Complex assembly required 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
            
               
                   
               
               
                 INK TYPE 
               
            
           
           
               
               
               
               
               
            
               
                   
                 Description 
                 Advantages 
                 Disadvantages 
                 Examples 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                 Aqueous, dye 
                 Water based ink which typically 
                 Environmentally friendly 
                 Slow drying 
                 Most existing ink jets 
               
               
                   
                 contains: water, dye, surfactant, 
                 No order 
                 Corrosive 
                 All IJ series ink jets 
               
               
                   
                 humectant, and biocide. Modern 
                   
                 Bleeds on paper 
                 Silverbrook, EP 0771 658 A2 
               
               
                   
                 ink dyes have high water- 
                   
                 May strikethrough 
                 and related patent applications 
               
               
                   
                 fastness, light fastness 
                   
                 Cockles paper 
               
               
                 Aqueous, pig- 
                 Water based ink which typically 
                 Environmentally friendly 
                 Slow drying 
                 IJ02, IJ04, IJ21, IJ26, IJ27, IJ30 
               
               
                 ment 
                 contains: water, pigment, 
                 No odor 
                 Corrosive 
                 Silverbrook, EP 0771 658 A2 
               
               
                   
                 surfactant, humectant, and 
                 Reduced bleed 
                 Pigment may clog nozzles 
                 and related patent applications 
               
               
                   
                 biocide. Pigments have an 
                 Reduced wicking 
                 Pigment may clog actuator 
                 Piezoelectric ink-jets 
               
               
                   
                 advantage in reduced bleed, 
                 Reduced strikethrough 
                 mechanisms 
                 Thermal ink jets (with signifi- 
               
               
                   
                 wicking and strikethrough. 
                   
                 Cockles paper 
                 cant restrictions) 
               
               
                 Methyl Ethyl 
                 MEK is a highly volatile solvent 
                 Very fast drying 
               
               
                 Ketone (MEK) 
                 used for industrial printing on 
                 Prints on various substrates such 
                 Odorous 
                 All IJ series ink jets 
               
               
                   
                 difficult surfaces such as 
                 as metals and plastics 
                 Flammable 
               
               
                   
                 aluminum cans. 
               
               
                 Alcohol 
                 Alcohol based inks can be used 
                 Fast drying 
                 Slight odor 
                 All IJ series ink jets 
               
               
                 (ethanol, 
                 where the printer must operate at 
                 Operates at sub-freezing 
                 Flammable 
               
               
                 2-butanol, and 
                 temperatures below the freezing 
                 temperatures 
               
               
                 others) 
                 point of water. An example of 
                 Reduced paper cockle 
               
               
                   
                 this is in-camera consumer 
                 Low cost 
               
               
                   
                 photographic printing. 
               
               
                 Phase change 
                 The ink is solid at room temper- 
                 No drying time-ink instantly 
                 High viscosity 
                 Tektronix hot melt piezoelectric 
               
               
                 (hot melt) 
                 ature, and is melted in the print 
                 freezes on the print medium 
                 Printed ink typically has a 
                 ink jets 
               
               
                   
                 head before jetting. Hot melt 
                 Almost any print medium can be 
                 ‘waxy’ feel 
                 1989 Nowak U.S. Pat. No. 
               
               
                   
                 inks are usually wax based, with 
                 used 
                 Printed pages may ‘block’ 
                 4,820,436 
               
               
                   
                 a melting point around 80° C.. 
                 No paper cockle occurs 
                 Ink temperature may be above 
                 All IJ series ink jets 
               
               
                   
                 After jetting the ink freezes 
                 No wicking occurs 
                 the curie pont of permanent 
               
               
                   
                 almost instantly upon contacting 
                 No bleed occurs 
                 magnets 
               
               
                   
                 the print medium or a transfer 
                 No strikthrough occurs 
                 Ink heaters consume power 
               
               
                   
                 roller. 
                   
                 Long warm-up time 
               
               
                 Oil 
                 Oil based inks are extensively 
                 High solubility medium for 
                 High viscosity: this is a signifi- 
                 All IJ series ink jets 
               
               
                   
                 used in offset printing. They 
                 some dyes 
                 cant limitation for use in ink 
               
               
                   
                 have advantages in improved 
                 Does not cockle paper 
                 jets, which usually require a low 
               
               
                   
                 characteristics on paper 
                 Does not wick through paper 
                 viscosity. Some short chain and 
               
               
                   
                 (especially no wicking or 
                   
                 multi-branched oils have a 
               
               
                   
                 cockle). Oil soluble dies and 
                   
                 sufficiently low viscosity. 
               
               
                   
                 pigments are required. 
                   
                 Slow drying 
               
               
                 Micro- 
                 A microemulsion is a stable, self 
                 Stop ink bleed 
                 Viscosity higher than water 
                 All IJ series ink jets 
               
               
                 emulsion 
                 forming emulsion of oil, water, 
                 High dye solubility 
                 Cost is slightly higher than 
               
               
                   
                 and surfactant. The characteristic 
                 Water, oil, and amphiphilic 
                 water based ink 
               
               
                   
                 drop size is less than 100 nm, 
                 soluble dies can be used 
                 High surfactant concentration 
               
               
                   
                 and is determined by the pre- 
                 Can stabilize pigment 
                 required (around 5%) 
               
               
                   
                 ferred curvature of the sur- 
                 suspensions 
               
               
                   
                 factant.