Patent Publication Number: US-6041600-A

Title: Utilization of quantum wires in MEMS actuators

Description:
FIELD OF THE INVENTION 
     The present invention relates to a thermal actuator device and, in particular, discloses a method of utilisation of quantum wires in MEMS actuators. 
     The present invention further relates to the construction of micro-electro mechanical systems (MEMS). 
     BACKGROUND OF THE INVENTION 
     MEMS processes are often characterised by the construction of conductive layers in multilayered structures such as actuator devices or the like. Often, it is important for these conductive layers to be in thermal contact with an adjacent material where the conductive layer is utilised as a heater element to instigate the actuation of an active device of the micro-electro mechanical system. The conductive layer material is typically a different material than the material utilised in the adjacent, thermally active layer, creating problems associated with the formation of such active, multilayered structures such as de-lamination and in-efficient thermal connection which can cause problems in the device performance and ultimately devices may stop functioning. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a MEMS construction which alleviates the aforementioned problems. 
     In accordance with a first aspect of the present invention there is provided a method of constructing one or more electrically conductive portions within a substantially non-conductive material comprising embedding quantum wires of a substantially conductive material within said portions. 
     In accordance with a second aspect of the present invention there is provided a thermal actuator comprising a substantially non-conductive, heat expansive material having a predetermined portion thereof rendered electrically conductive by the incorporation of a series of quantum wires of a substantially conductive material. 
     Preferably, the non-conductive, expansive material comprises substantially polytetrafluoroethylene and the conductive material comprises substantially copper. 
     In accordance with a third aspect of the present invention there is provided a thermal actuator comprising first and second layers of substantially non-conductive, heat expansive materials, wherein one of said layers incorporates quantum wires of a substantially conductive material interposed with said substantially non-conductive, expansive material. 
     Preferably, the non-conductive, expansive material comprises substantially polytetrafluoroethylene and the conductive material comprises substantially copper. 
    
    
     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 of 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. 
    
    
     DESCRIPTION OF PREFERRED AND OTHER EMBODIMENTS 
     The preferred embodiment of the present invention will be described in respect of an ink jet print head construction which utilises quantum wires embedded in a thermal expansion layer. The present invention should, however, not necessarily be restricted to the field of ink jet printing, as will be readily evident. 
     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 an 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 FIG. 1, there are illustrated two adjoining inkjet nozzles 10 constructed in accordance with the preferred embodiment. Each nozzle 10, 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. 
     The 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 arrangement 10. The exploded perspective view illustrates the form of construction of each layer of a simple nozzle arrangement 10. 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. (&#34;Individual single-wall carbon nano-tubes as quantum wires&#34; by Tans et al Nature, Volume 386, 3rd April 1997 at pages 474-477). The PTFE layer 40 includes tubes 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 &#34;hot spots&#34; 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. 
     It would be appreciated by a person skilled in the art that numerous variations and/or modifications may be made to the present invention as shown in the specific embodiment without departing from the spirit or scope of the invention as broadly described. The present embodiment is, therefore, to be considered in all respects to be illustrative and not restrictive. 
     Ink Jet Technologies 
     The embodiments of the invention use an ink jet printer type device. Of course many different devices could be used. However presently popular ink jet printing technologies are unlikely to be suitable. 
     The most significant problem with thermal inkjet 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 inkjet 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 inkjet 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 print head, but is a major impediment to the fabrication of pagewide print heads with 19,200 nozzles. 
     Ideally, the inkjet 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 inkjet 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 inkjet systems described below with differing levels of difficulty. 45 different inkjet technologies have been developed by the Assignee to give a wide range of choices for high volume manufacture. These technologies form part of separate applications assigned to the present Assignee as set out in the table below. 
     The inkjet 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 print head is designed to be a monolithic 0.5 micron CMOS chip with MEMS post processing. For color photographic applications, the print head is 100 mm long, with a width which depends upon the inkjet type. The smallest print head designed is IJ38, which is 0.35 mm wide, giving a chip area of 35 square mm. The print heads each contain 19,200 nozzles plus data and control circuitry. 
     Ink is supplied to the back of the print head by injection molded plastic ink channels. The molding requires 50 micron features, which can be created using a lithographically micromachined insert in a standard injection molding tool. Ink flows through holes etched through the wafer to the nozzle chambers fabricated on the front surface of the wafer. The print head is connected to the camera circuitry by tape automated bonding. 
     Cross-Referenced Applications 
     The following table is a guide to cross-referenced patent applications filed concurrently herewith and discussed hereinafter with the reference being utilized in subsequent tables when referring to a particular case: 
     
         __________________________________________________________________________
Docket                                                                    
    US Patent                                                             
No. Application No.                                                       
            Title                                                         
__________________________________________________________________________
IJ01US                                                                    
    09/112,751                                                            
            Radiant Plunger Ink Jet Printer                               
IJ02US                                                                    
    09/112,787                                                            
            Electrostatic Ink Jet Printer                                 
IJ03US                                                                    
    09/112,802                                                            
            Planar Thermoelastic Bend Actuator Ink Jet                    
IJ04US                                                                    
    09/112,803                                                            
            Stacked Electrostatic Ink Jet Printer                         
IJ05US                                                                    
    09/113,097                                                            
            Reverse Spring Lever Ink Jet Printer                          
IJ06US                                                                    
    09/113,099                                                            
            Paddle Type Ink Jet Printer                                   
IJ07US                                                                    
    09/113,084                                                            
            Permanent Magnet Electromagnetic Ink Jet Printer              
IJ08US                                                                    
    09/113,066                                                            
            Planar Swing Grill Electromagnetic Ink Jet Printer            
IJ09US                                                                    
    09/112,778                                                            
            Pump Action Refill Ink Jet Printer                            
IJ10US                                                                    
    09/112,779                                                            
            Pulsed Magnetic Field Ink Jet Printer                         
IJ11US                                                                    
    09/113,077                                                            
            Two Plate Reverse Firing Electromagnetic Ink Jet Printer      
IJ13US                                                                    
    09/112,818                                                            
            Gear Driven Shutter Ink Jet Printer                           
IJ14US                                                                    
    09/112,816                                                            
            Tapered Magnetic Pole Electromagnetic Ink Jet Printer         
IJ15US                                                                    
    09/112,772                                                            
            Linear Spring Electromagnetic Grill Ink Jet Printer           
IJ16US                                                                    
    09/112,819                                                            
            Lorenz Diaphragm Electromagnetic Ink Jet Printer              
IJ17US                                                                    
    09/112,815                                                            
            PTFE Surface Shooting Shuttered Oscillating Pressure Ink Jet  
            Printer                                                       
IJ18US                                                                    
    09/113,096                                                            
            Buckle Grip Oscillating Pressure Ink Jet Printer              
IJ19US                                                                    
    09/113,068                                                            
            Shutter Based Ink Jet Printer                                 
IJ20US                                                                    
    09/113,095                                                            
            Curing Calyx Thermoelastic Ink Jet Printer                    
IJ21US                                                                    
    09/112,808                                                            
            Thermal Actuated Ink Jet Printer                              
IJ22US                                                                    
    09/112,809                                                            
            Iris Motion Ink Jet Printer                                   
IJ23U5                                                                    
    09/112,780                                                            
            Direct Firing Thermal Bend Actuator Ink Jet Printer           
IJ24U5                                                                    
    09/113,083                                                            
            Conductive PTFE Ben Activator Vented Ink Jet Printer          
IJ25US                                                                    
    09/113,121                                                            
            Magnetostrictive Ink Jet Printer                              
IJ26U5                                                                    
    09/113,122                                                            
            Shape Memory Alloy Ink Jet Printer                            
IJ27U5                                                                    
    09/112,793                                                            
            Buckle Plate Ink Jet Printer                                  
IJ28U5                                                                    
    09/112,794                                                            
            Thermal Elastic Rotary Impeller Ink Jet Printer               
IJ29U5                                                                    
    09/113,128                                                            
            Thermoelastic Bend Actuator Ink Jet Printer                   
IJ30US                                                                    
    09/113,127                                                            
            Thermoelastic Bend Actuator Using PTFE and Corrugated         
            Copper Ink Jet Printer                                        
IJ31US                                                                    
    09/112,756                                                            
            Bend Actuator Direct Ink Supply Ink Jet Printer               
IJ32US                                                                    
    09/112,755                                                            
            A High Young&#39;s Modulus Thermoelastic Ink Jet Printer          
IJ33US                                                                    
    09/112,754                                                            
            Thermally actuated slotted chamber wall ink jet printer       
IJ34U5                                                                    
    09/112,811                                                            
            Ink Jet Printer having a thermal actuator comprising an       
            external coiled spring                                        
IJ35U5                                                                    
    09/112,812                                                            
            Trough Container Ink Jet Printer                              
IJ36U5                                                                    
    09/112,813                                                            
            Dual Chamber Single Vertical Actuator Ink Jet                 
IJ37US                                                                    
    09/112,814                                                            
            Dual Nozzle Single Horizontal Fulcrum Actual or Ink Jet       
IJ38US                                                                    
    09/112,764                                                            
            Dual Nozzle Single Horizontal Actuator Ink Jet                
IJ39U5                                                                    
    09/112,765                                                            
            A single bend actuator cupped paddle inkjet printing device   
IJ40US                                                                    
    09/112,767                                                            
            A thermally actuated inkjet printer having a series of        
            thermal                                                       
            actuator units                                                
IJ41US                                                                    
    09/112,768                                                            
            A thermally actuated inkjet printer including a tapered       
            heater                                                        
            element                                                       
IJ42US                                                                    
    09/112,807                                                            
            Radial Back-Curing Thermoelastic Ink Jet                      
IJ43US                                                                    
    09/112,806                                                            
            Inverted Radial Back-Curing Thermoelastic Ink Jet             
IJ44U5                                                                    
    09/112,820                                                            
            Surface bend actuator vented ink supply ink jet printer       
IJ45US                                                                    
    09/112,821                                                            
            Coil Actuated Magnetic Plate Ink Jet Printer                  
__________________________________________________________________________
 
    
     Tables of Drop-on-Demand Inkjets 
     Eleven important characteristics of the fundamental operation of individual inkjet 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 inkjet 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 inkjet nozzle. While not all of the possible combinations result in a viable inkjet technology, many million configurations are viable. It is clearly impractical to elucidate all of the possible configurations. Instead, certain inkjet types have been investigated in detail. These are designated IJ01 to IJ45 above. 
     Other inkjet configurations can readily be derived from these 45 examples by substituting alternative configurations along one or more of the 11 axes. Most of the IJ01 to IJ45 examples can be made into inkjet print heads with characteristics superior to any currently available inkjet 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 include: Home printers, Office network printers, Short run digital printers, Commercial print systems, Fabric printers, Pocket printers, Internet WWW printers, Video printers, Medical imaging, Wide format printers, Notebook PC printers, Fax machines, Industrial printing systems, Photocopiers, Photographic minilabs etc. 
     The information associated with the aforementioned 11 dimensional matrix are set out in the following tables. 
     
            - Description Advantages Disadvantages Examples
   ACTUATOR MECHANISM (APPLIED ONLY TO SELECTED INK DROPS)
   Actuator
   Mechanism
   Thermal An electrothermal heater heats the ♦Large force
 generated ♦High power ♦Canon Bubblejet
        bubble ink to above boiling point, ♦Simple construct
  ion ♦Ink carrier limited to water 1979 Endo et al GB
        transferring significant heat to the ♦No moving
 parts ♦Low efficiency patent 2,007,162
    aqueous ink. A bubble nucleates and ♦Fast operation
 ♦High temperatures required ♦Xerox heater-in-
  pit
    quickly forms, expelling the ink. ♦Small chip area
 required for ♦High mechanical stress 1990 Hawkins et al
      The efficiency of the process is low, actuator ♦Unusua
  l materials required U.S. Pat. No. 4,899,181
    with typically less than 0.05% of the  ♦Large drive
 transistors ♦Hewlett-Packard TIJ
    electrical energy being transformed  ♦Cavitation causes
   actuator failure 1982 Vaught et al
    into kinetic energy of the drop.  ♦Kogation reduces
 bubble formation U.S. Pat. No. 4,490,728
      ♦Large print heads are difficult to
      fabricate
   Piezoelectric A piezoelectric crystal such as lead ♦Low
 power consumption. ♦Very large area required for actuator
 ♦Kyser et al U.S. Pat. No.
    lanthanum zirconate (PZT) is ♦Many ink types can be
 used ♦Difficult to integrate with electronics 3,946,398
      electrically activated, and either ♦Fast operation
 ♦High voltage drive transistors ♦Zoltan U.S.
   Pat. No.
    expands, shears, or bends to apply ♦High efficiency
 required 3,683,212
    pressure to the ink, ejecting drops.  ♦Full pagewidth
 print heads impractical ♦1973 Stemme U.S. Pat. No.
             due to actuator size 3,747,120
      ♦Requires electrical poling in high field .diamond-sol
  id.Epson Stylus
      strengths during manufacture ♦Tektronix
       ♦IJ04
   Electro- An electric field is used to activate ♦Low
 power consumption ♦Low maximum strain (approx. 0.01%)
 ♦Seiko Epson, Usui et
   strictive electrostriction in relaxor materials ♦Many
 ink types can be used ♦Large area required for actuator
 all JP 253401/96
    such as lead lanthanum zirconate ♦Low thermal expansion
   due to low strain ♦IJ04
    titanate (PLZT) or lead magnesium ♦Electric field
 strength ♦Response speed is marginal (˜10 μs)
       niobate (PMN). required (approx. 3.5 V/μm) ♦High
 voltage drive transistors required
     can be generated without ♦Full pagewidth print heads
 impractical
     difficulty due to actuator size
     ♦Does not require electrical
     poling
   Ferroelectric An electric field is used to induce a ♦Low
   power consumption ♦Difficult to integrate with electronic
  s ♦IJ04
    phase transition between the ♦Many ink types can be
 used ♦Unusual materials such as PLZSnT are
    antiferroelectric (AFE) and ♦Fast operation (&lt;1 μs)
 required
    ferroelectric (FE) phase. Perovskite ♦Relatively high
 longitudinal ♦Actuators require a large area
    materials such as tin modified lead strain
    lanthanum zirconate titanate ♦High efficiency
    (PLZSnT) exhibit large strains of up ♦Electric field
 strength of
    to 1% associated with the AFE to FE around 3 V/μm can be
    phase transition, readily provided
   Electrostatic Conductive plates are separated by a ♦Low
 power consumption ♦Difficult to operate electrostatic
 ♦IJ02, IJ04
   plates compressible or fluid dielectric ♦Many ink types
 can be used devices in an aqueous environment
    (usually air). Upon application of a ♦Fast operation
 ♦The electrostatic actuator will normally
    voltage, the plates attract each other  need to be separated from the
   ink
    and displace ink, causing drop  ♦Very large area
 required to achieve
    ejection. The conductive plates may  high forces
    be in a comb or honeycomb  ♦High voltage drive transisto
  rs may be
    structure, or stacked to increase the  required
    surface area and therefore the force.  ♦Full pagewidth
 print heads are not
      competitive due to actuator size
   Electrostatic A strong electric field is applied to ♦Low
   current consumption ♦High voltage required .diamond-solid
  .1989 Saito et al, U.S. Pat. No.
   pull on ink the ink, whereupon electrostatic ♦Low
 temperature ♦May be damaged by sparks due to air 4,799,068
    attraction accelerates the ink towards  breakdown ♦1989
   Miura et al,
    the print medium.  ♦Required field strength increases
 as the U.S. Pat. No. 4,810,954
      drop size decreases ♦Tone-jet
      ♦High voltage drive transistors required
      ♦Electrostatic field attracts dust
   Permanent An electromagnet directly attracts a ♦Low
 power consumption ♦Complex fabrication ♦IJ07,
   IJ10
   magnet permanent magnet, displacing ink ♦Many ink types
 can be used ♦Permanent magnetic material such as
   electro- and causing drop ejection. Rare earth ♦Fast
 operation Neodymium Iron Boron (NdFeB)
   magnetic magnets with a field strength around ♦High
 efficiency required.
    1 Tesla can be used. Examples are: ♦Easy extension from
   single ♦High local currents required
    Samarium Cobalt (SaCo) and nozzles to pagewidth print ♦C
  opper metalization should be used for
    magnetic materials in the heads long electromigration lifetime and
 low
    neodymium iron boron family  resistivity
    (NdFeB, NdDyFeBNb, NdDyFeB,  ♦Pigmented inks are
 usually infeasible
    etc)  ♦Operating temperature limited to the
      Curie temperature (around 540 K)
   Soft magnetic A solenoid induced a magnetic field ♦Low
 power consumption ♦Complex fabrication ♦IJ01,
   IJ05, IJ08, IJ10
   core electro- in a soft magnetic core or yoke ♦Many ink
 types can be used ♦Materials not usually present in a
 ♦IJ12, IJ14, IJ15, IJ17
   magnetic fabricated from a ferrous material ♦Fast
 operation CMOS fab such as NiFe, CoNiFe, or
    such as electroplated iron alloys such ♦High efficiency
   CoFe are required
    as CoNiFe [1], CoFe, or NiFe alloys. ♦Easy extension
 from single ♦High local currents required
    Typically, the soft magnetic material nozzles to pagewidth print
 ♦Copper metalization should be used for
    is in two parts; which are normally heads long electromigration
 lifetime and low
    held apart by a spring. When the  resistivity
    solenoid is actuated, the two parts  ♦Electroplating is
   required
    attract, displacing the ink.  ♦High saturation flux
 density is required
      (2.0-2.1 T is achievable with CoNiFe
      [1])
   Magnetic The Lorenz force acting on a current ♦Low power
   consumption ♦Force acts as a twisting motion .diamond-sol
  id.IJ06, IJ11, IJ13, IJ16
   Lorenz force carrying wire in a magnetic field is ♦Many
 ink types can be used ♦Typically, only a quarter of the
      utilized. ♦Fast operation solenoid length provides
 force in a
    This allows the magnetic field to be ♦High efficiency
 useful direction
    supplied externally to the print head, ♦Easy extension
 from single ♦High local currents required
    for example with rare earth nozzles to pagewidth print ♦
  Copper metalization should be used for
    permanent magnets. heads long electromigration lifetime and low
         Only the current carrying wire need  resistivity
    be fabricated on the print-head,  ♦Pigmented inks are
 usually infeasible
    simplifying materials requirements.
   Magneto- The actuator uses the giant ♦Many ink types can
   be used ♦Force acts as a twisting motion ♦F
  ischenbeck, U.S. Pat. No.
   striction magnetostrictive effect of materials ♦Fast
 operation ♦Unusual materials such as Terfenol-D 4,032,929
    such as Terfenol-D (an alloy of ♦Easy extension from
 single are required ♦IJ25
    terbium, dysprosium and iron nozzles to pagewidth print .diamond-solid
  .High local currents required
    developed at the Naval Ordnance heads ♦Copper metalizati
  on should be used for
    Laboratory, hence Ter-Fe-NOL). For ♦High force is
 available long electromigration lifetime and low
    best efficiency, the actuator should  resistivity
    be pre-stressed to approx. 8 MPa.  ♦Pre-stressing may
 be required
   Surface Ink under positive pressure is held in ♦Low
 power consumption ♦Requires. supplementary force to effect
   ♦Silverbrook, EP 0771
   tension a nozzle by surface tension. The ♦Simple
 construction drop separation 658 A2 and related
   reduction surface tension of the ink is reduced ♦No
 unusual materials ♦Requires special ink surfactants patent
   applications
    below the bubble threshold, causing required in fabrication .diamond-s
  olid.Speed may be limited by surfactant
    the ink to egress from the nozzle. ♦High efficiency
 properties
     ♦Easy extension from single
     nozzles to pagewidth print
     heads
   Viscosity The ink viscosity is locally reduced ♦Simple
 construction ♦Requires supplementary force to effect
 ♦Silverbrook, EP 0771
   reduction to select which drops are to be ♦No unusual
 materials drop separation 658 A2 and related
    ejected. A viscosity reduction can be required in fabrication
 ♦Requires special ink viscosity patent applications
          achieved electrothermally with most ♦Easy
 extension from single properties
    inks, but special inks can be nozzles to pagewidth print .diamond-soli
  d.High speed is difficult to achieve
    engineered for a 100:1 viscosity heads ♦Requires
 oscillating ink pressure
    reduction.  ♦A high temperature difference
      (typically 80 degrees) is required
   Acoustic An acoustic wave is generated and ♦Can operate
 without a ♦Complex drive circuitry ♦1993
 Hadimioglu et
    focused upon the drop ejection nozzle plate. ♦Complex
 fabrication al, EUP 550,192
    region.   ♦Low efficiency ♦1993 Elrod et
 al, EUP
      ♦Poor control of drop position 572,220
      ♦Poor control of drop volume
   Thermoelastic An actuator which relies upon ♦Low power
 consumption ♦Efficient aqueous operation requires a
 ♦IJ03, IJ09, IJ17, IJ18
   bend actuator differential thermal expansion upon ♦Many
 ink types can be used thermal insulator on the hot side ♦IJ
  19, IJ20, IJ21, IJ22
    Joule heating is used. ♦Simple planar fabrication
 ♦Corrosion prevention can be difficult ♦IJ23,
   IJ24, IJ27, IJ28
     ♦Small chip area required for ♦Pigmented
   inks may be infeasible, as ♦IJ29, IJ30, IJ31, IJ32
          each actuator pigment particles may jam the bend ♦
  IJ33, IJ34, IJ35, IJ36
     ♦Fast operation actuator ♦IJ37, IJ38,
 IJ39, IJ40
     ♦High efficiency  ♦IJ41
     ♦CMOS 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 ♦High force can be
 generated ♦Requires special material (e.g. PTFE) .diamond-s
  olid.IJ09, IJ17, IJ18, IJ20
   thermoelastic coefficient of thermal expansion ♦PTFE is
 a candidate for low ♦Requires a PTFE deposition process,
 ♦IJ21, IJ22, IJ23, IJ24
   actuator (CTE) such as dielectric constant which is not yet standard
 in ULSI fabs ♦IJ27, IJ28, IJ29, IJ30
    polytetrafluoroethylene (PTFE) is insulation in ULSI ♦PT
  FE deposition cannot be followed ♦IJ31, IJ42, IJ43, IJ44
    used. As high CTE materials are ♦Very low power with
 high temperature (above 350°
  C.)                                    usually non-conductive, a heater
   consumption processing
    fabricated from a conductive ♦Many ink types can be
 used ♦Pigmented inks may be infeasible, as
    material is incorporated. A 50 μm ♦Simple planar
 fabrication pigment particles may jam the bend
    long PTFE bend actuator with ♦Small chip area required
 for actuator
    polysilicon heater and 15 mW power each actuator
    input can provide 180 μN force and ♦Fast operation
     10 μm deflection. Actuator motions ♦High efficiency
    include: CMOS compatible voltages
    1) Bend and currents
    2) Push ♦Easy extension from single
    3) Buckle nozzles to pagewidth print
    4) Rotate heads
   Conductive A polymer with a high coefficient of ♦High
 force can be generated ♦Requires special materials
 ♦IJ24
   polymer thermal expansion (such as PTFE) is ♦Very low
 power development (High CTE conductive
   thermoelastic doped with conducting substances to consumption polymer)
   actuator. increase its conductivity to about 3 ♦Many ink
   types can be used ♦Requires a PTFE deposition process,
     orders of magnitude below that of ♦Simple planar
 fabrication which is not yet standard in ULSI fabs
    copper. The conducting polymer ♦Small chip area
 required for ♦PTFE deposition cannot be followed
    expands when resistively heated. each actuator with high temperature
 (above 350°
  C.)                                                     Examples of
 conducting dopants ♦Fast operation processing
    include: ♦High efficiency ♦Evaporation
 and CVD deposition
    1) Carbon nanotubes ♦CMOS compatible voltages techniques
   cannot be used
    2) Metal fibers and currents ♦Pigmented inks may be
 infeasible, as
    3) Conductive polymers such as ♦Easy extension from
 single pigment particles may jam the bend
    doped polythiophene nozzles to pagewidth print actuator
    4) Carbon granules heads
   Shape memory A shape memory alloy such as TiNi ♦High
 force is available ♦Fatigue limits maximum number of
 ♦IJ26
   alloy (also known as Nitinol - Nickel (stresses of hundreds of cycles
    Titanium alloy developed at the MPa) ♦Low strain (1%)
 is required to extend
    Naval Ordnance Laboratory) is ♦Large strain is available
   fatigue resistance
    thermally switched between its weak (more than 3%) ♦Cycl
  e rate limited by heat removal
    martensitic state and its high ♦High corrosion resistanc
  e ♦Requires unusual materials (TiNi)
    stiffness austenic state. The shape of ♦Simple construct
  ion ♦The latent heat of transformation must
    the actuator in its martensitic state is ♦Easy extension
   from single be provided
    deformed relative to the austenic nozzles to pagewidth print .diamond-
  solid.High current operation
    shape. The shape change causes heads ♦Requires pre-stres
  sing to distort the
    ejection of a drop. ♦Low voltage operation martensitic
 state
   Linear Linear magnetic actuators include ♦Linear
 Magnetic actuators ♦Requires unusual semiconductor
 ♦IJ12
   Magnetic the Linear Induction Actuator (LIA), can he constructed with
 materials such as soft magnetic alloys
   Actuator Linear Permanent Magnet high thrust, long travel, and (e.g.
 CoNiFe [1])
    Synchronous Actuator (LPMSA), high efficiency using planar .diamond-so
  lid.Some varieties also require permanent
    Linear Reluctance Synchronous semiconductor fabrication magnetic
 materials such as
    Actuator (LRSA), Linear Switched techniques Neodymium iron boron
 (NdFeB)
    Reluctance Actuator (LSRA), and ♦Long actuator travel
 is ♦Requires complex multi-phase drive
    the Linear Stepper Actuator (LSA). available circuitry
     ♦Medium force is available ♦High current
   operation
     ♦Low voltage operation
   BASIC OPERATION MODE
   Operational
   mode
   Actuator This is the simplest mode of ♦Simple operation
 ♦Drop repetition rate is usually limited ♦The
  rmal inkjet
   directly operation: the actuator directly ♦No external
 fields required to less than 10 KHz. However, this is ♦Piez
  oelectric inkjet
   pushes ink supplies sufficient kinetic energy to ♦Satelli
  te drops can be not fundamental to the method, but is ♦IJ0
  1, IJ02, IJ03, IJ04
    expel the drop. The drop must have a avoided if drop velocity is
 related to the refill method normally ♦IJ05, IJ06, IJ07,
 IJ09
    sufficient velocity to overcome the less than 4 m/s used .diamond-soli
  d.IJ11, IJ12, IJ14, IJ16
    surface tension ♦Can be efficient, depending .diamond-so
  lid.All of the drop kinetic energy must be ♦IJ20, IJ22,
 IJ23, IJ24
     upon the actuator used provided by the actuator ♦IJ25,
   IJ26, IJ27, IJ28
      ♦Satellite drops usually form if drop ♦I
  J29, IJ30, IJ31, IJ32
      velocity is greater than 4.5 m/s ♦IJ33, IJ34, IJ35,
 IJ36
       ♦IJ37, IJ38, IJ39, IJ40
       ♦IJ41, IJ42, IJ43, IJ44
   Proximity The drops to be printed are selected ♦Very
 simple print head ♦Requires close proximity between the
 ♦Silverbrook, EP 0771
    by some manner (e.g. thermally fabrication can be used print head and
   the print media or 658 A2 and related
    induced surface tension reduction of ♦The drop selection
   means transfer roller patent applications
    pressurized ink). Selected drops are does not need to provide the
 ♦May require two print heads printing
    separated from the ink in the nozzle energy required to separate
 alternate rows of the image
    by contact with the print medium or the drop from the nozzle .diamond-
  solid.Monolithic color print heads are
    a transfer roller.  difficult
   Electrostatic The drops to be printed are selected ♦Very
   simple print head ♦Requires very high electrostatic
 field ♦Silverbrook, EP 077
   pull on ink by some manner (e.g. thermally fabrication can be used
 ♦Electrostatic field for small nozzle 658 A2 and related
     induced surface tension reduction of ♦The drop
 selection means sizes is above air breakdown patent applications
           pressurized ink). Selected drops are does not need to provide
 the ♦Electrostatic field may attract dust ♦To
  ne-Jet
    separated from the ink in the nozzle energy required to separate
        by a strong electric field. the drop from the nozzle
   Magnetic pull The drops to be printed are selected ♦Very
   simple print head ♦Requires magnetic ink ♦S
  ilverbrook, EP 0771
   on ink by some manner (e.g. thermally fabrication can be used .diamond-
  solid.Ink colors other than black are difficult 658 A2 and related
        induced surface tension reduction of ♦The drop
 selection means ♦Requires very high magnetic fields patent
   applications
    pressurized ink). Selected drops are does not need to provide the
       separated from the ink in the nozzle energy required to separate
     by a strong magnetic held acting on the drop from the nozzle
           the magnetic ink.
   Shutter The actuator moves a shutter to ♦High speed (&gt;50
   KHz) ♦Moving parts are required ♦IJ13,
 IJ17, IJ21
    block ink flow to the nozzle. The ink operation can be achieved
 ♦Requires ink pressure modulator
    pressure is pulsed at a multiple of the due to reduced refill time
 ♦Friction and wear must be considered
    drop ejection frequency. ♦Drop timing can be very
 ♦Stiction is possible
     accurate
     ♦The actuator energy can be
     very low
   Shuttered grill The actuator moves a shutter to ♦Actuator
  s with small travel ♦Moving parts are required .diamond-so
  lid.IJ08, IJ15, IJ18, IJ19
    block ink flow through a grill to the can be used ♦Requi
  res ink pressure modulator
    nozzle. The shutter movement need ♦Actuators with small
   force ♦Friction and wear must be considered
    only be equal to the width of the grill can be used ♦Sti
  ction is possible
    holes. ♦High speed (&gt;50 KHz)
     operation can be achieved
   Pulsed A pulsed magnetic field attracts an ♦Extremely
 low energy ♦Requires an external pulsed magnetic .diamond-s
  olid.IJ10
   magnetic pull `ink pusher` at the drop ejection operation is possible
 field
   on ink pusher frequency. An actuator controls a ♦No heat
   dissipation ♦Requires special materials for both the
       catch, which prevents the ink pusher problems actuator and the ink
   pusher
    from moving when a drop is not to  ♦Complex construction
    be ejected.
   AUXILIARY MECHANISM (APPLIED TO ALL NOZZLES)
   Auxiliary
   Mechanism
   None The actuator directly fires the ink ♦Simplicity of
 construction ♦Drop ejection energy must be supplied
 ♦Most inkjets,
    drop, and there is no external field or ♦Simplicity of
 operation by individual nozzle actuator including
    other mechanism required ♦Small physical size  piezoelec
  tric and
       thermal bubble.
       ♦IJ01-IJ07, IJ09, IJ11
       ♦IJ12, IJ14, IJ20, IJ22
       ♦IJ23-IJ45
   Oscillating ink The ink pressure oscillates, ♦Oscillating
   ink pressure can ♦Requires external ink pressure
 ♦Silverbrook, EP 0771
   pressure providing much of the drop ejection provide a refill pulse,
 oscillator 658 A2 and related
   (including energy. The actuator selects which allowing higher operating
   ♦Ink pressure phase and amplitude must patent application
  s
   acoustic drops are to be fired by selectively speed be carefully
 controlled ♦IJ08, IJ13, IJ15, IJ17
   stimulation) blocking or enabling nozzles. The ♦The
 actuators may operate ♦Acoustic reflections in the ink
 chamber ♦IJ18, IJ19, IJ21
    ink pressure oscillation may he with much tower energy must be
 designed for
    achieved by vibrating the print head, ♦Acoustic lenses
 can be used
    or preferably by an actuator in the to focus the sound on the
           ink supply. nozzles
   Media The print head is placed in close ♦Low power
 ♦Precision assembly required ♦Silverbrook,
 EP 0771
   proximity proximity to the print medium. ♦High accuracy
 ♦Paper fibers may cause problems 658 A2 and related
          Selected drops protrude from the ♦Simple print
 head ♦Cannot print on rough substrates patent applications
    print head further than unselected construction
    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 roller ♦H
  igh accuracy ♦Bulky ♦Silverbrook, EP 0771
     instead of straight to the print ♦Wide range of print
 ♦Expensive 658 A2 and related
    medium. A transfer roller can also be substrates can be used .diamond-
  solid.Complex construction patent applications
    used for proximity drop separation. ♦Ink can be dried
 on the  ♦Tektronix hot melt
     transfer roller  piezoelectric inkjet
       ♦Any of the IJ series
   Electrostatic An electric field is used to accelerate ♦Lo
  w power ♦Field strength required for separation .diamond-s
  olid.Silverbrook, EP 0771
    selected drops towards the print ♦Simple print head of
 small drops is near or above air 658 A2 and related
    medium. constriction breakdown patent applications
       ♦Tone-Jet
   Direct A magnetic field is used to accelerate ♦Low power
   ♦Requires magnetic ink ♦Silverbrook, EP
 0771
   magnetic field selected drops of magnetic ink ♦Simple
 print head ♦Requires strong magnetic field 658 A2 and
 related
    towards the print medium. construction  patent applications
   Cross The print head is placed in a constant ♦Does not
 require magnetic ♦Requires external magnet ♦I
  J06, IJ16
   magnetic field magnetic field. The Lorenz force in a materials to be
 integrated in ♦Current densities may be high,
    current carrying wire is used to move the print head resulting in
 electromigration problems
    the actuator. manufacturing process
   Pulsed A pulsed magnetic field is used to ♦Very low
 power operation ♦Complex print head construction .diamond-s
  olid.IJ10
   magnetic field cyclically attract a paddle, which is possible.
 ♦Magnetic materials required in print
    pushes on the ink. A small actuator ♦Small print head
 size head
    moves a catch, which selectively
    prevents the paddle from moving.
   ACTUATOR AMPLIFICATION OR MODIFICATION METHOD
   Actuator
   amplification
   None No actuator mechanical ♦Operational simplicity
 ♦Many actuator mechanisms have ♦Thermal
 Bubble
    amplification is used. The actuator  insufficient travel, or insuffici
  ent force, Inkjet
    directly drives the drop ejection  to efficiently drive the drop
 ejection ♦IJ01, IJ02, IJ06, IJ07
    process.  process ♦IJ16, IJ25, IJ26
   Differential An actuator material expands more ♦Provides
   greater travel in a ♦High stresses are involved .diamond-
  solid.Piezoelectric
   expansion on one side than on the other. The reduced print head area
 ♦Care must be taken that the materials ♦IJ03,
   IJ09, IJ17-IJ24
   bend actuator expansion may be thermal, ♦The bend
 actuator converts do not delaminate ♦IJ27, IJ29-IJ39 IJ42,
    piezoelectric, magnetostrictive, or a high force low travel .diamond-s
  olid.Residual bend resulting from high ♦IJ43, IJ44
          other mechanism. actuator mechanism to high temperature or high
   stress during
     travel, lower force formation
     mechanism.
   Transient bend A trilayer bend actuator where the ♦Very
 good temperature ♦High stresses are involved .diamond-solid
  .IJ40, IJ41
   actuator two outside layers are identical. This stability .diamond-soli
  d.Care must be taken that the materials
    cancels bend due to ambient ♦High speed, as a new drop
 do not delaminate
    temperature and residual stress. The can be fired before heat
           actuator only responds to transient dissipates
    heating of one side or the other. ♦Cancels residual
 stress of
     formation
   Actuator stack A series of thin actuators are stacked. ♦I
  ncreased travel ♦Increased fabrication complexity
 ♦Some piezoelectric
    This can be appropriate where ♦Reduced drive voltage
 ♦Increased possibility of short circuits ink jets
    actuators require high electric field  due to pinholes ♦
  IJ04
    strength, such as electrostatic and
    piezoelectric actuators.
   Multiple Multiple smaller actuators are used ♦Increases
 the force available ♦Actuator forces may not add linearly,
   ♦IJ12, IJ13, IJ18, IJ20
   actuators simultaneously to move the ink. from an actuator reducing
 efficiency ♦IJ22, IJ28, IJ42, IJ43
    Each actuator need provide only a ♦Multiple actuators
 can be
    portion of the force required. positioned to control ink
     flow accurately
   Linear Spring A linear spring is used to transform a ♦Mat
  ches low travel actuator ♦Requires print head area for
 the spring ♦IJ15
    motion with small travel and high with higher travel
    force into a longer travel, lower force requirements
    motion. ♦Non-contact method of
     motion transformation
   Reverse spring The actuator loads a spring. When ♦Better
   coupling to the ink ♦Fabrication complexity .diamond-soli
  d.IJ05, IJ11
    the actuator is tuned off, the spring  ♦High stress in
 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.
   Coiled A bend actuator is coiled to provide ♦Increases
 travel ♦Generally restricted to planar ♦IJ17,
   IJ21, IJ34, IJ35
   actuator greater travel in a reduced chip area. ♦Reduces
   chip area implementations due to extreme
     ♦Planar implementations are fabrication difficulty in
 other
     relatively easy to fabricate. orientations.
   Flexure bend A bend actuator has a small region ♦Simple
 means of increasing ♦Care must be taken not to exceed the
 ♦IJ10, IJ19, IJ33
   actuator near the fixture point, which flexes travel of a bend
 actuator elastic limit in the flexure area
    much more readily than the  ♦Stress distribution is
 very uneven
    remainder of the actuator. The  ♦Difficult to accurately
   model with
    actuator flexing is effectively  finite element analysis
    converted from an even coiling to an
    angular bend, resulting in greater
    travel of the actuator tip.
   Gears Gears can be used to increase travel ♦Low force,
 low travel ♦Moving parts are required ♦IJ13
    at the expense of duration. Circular actuators can be used .diamond-so
  lid.Several actuator cycles are required
    gears, rack and pinion, ratchets, and ♦Can be fabricated
   using ♦More complex drive electronics
    other gearing methods can be used. standard surface MEMS .diamond-soli
  d.Complex construction
     processes ♦Friction, friction, and wear are possible
    Catch The actuator controls a small catch. ♦Very low
 actuator energy ♦Complex construction ♦IJ10
    The catch either enables or disables ♦Very small
 actuator size ♦Requires external force
    movement of an ink pusher that is  ♦Unsuitable for
 pigmented inks
    controlled in a bulk manner.
   Buckle plate A buckle plate can be used to change ♦Very
 fast movement ♦Must stay within elastic limits of the
 ♦S. Hirata et al, &#34;An
    a slow actuator into a fast motion. It achievable materials for long
 device life Ink-jet Head . . . &#34;,
    can also convert a high force, low  ♦High stresses
 involved Proc. IEEE MEMS,
    travel actuator into a high travel,  ♦Generally high
 power requirement Feb. 1996, pp 418-
    medium force motion.   423.
       ♦IJ18, IJ27
   Tapered A tapered magnetic pole can increase ♦Linearizes
   the magnetic ♦Complex construction ♦IJ14
    magnetic pole travel at the expense of force. force/distance curve
     Lever A lever and fulcrum is used to ♦Matches low
 travel actuator ♦High stress around the fulcrum .diamond-so
  lid.IJ32, IJ36, IJ37
    transform a motion with small travel with higher travel
    and high force into a motion with requirements
    longer travel and lower force. The ♦Fulcrum area has no
   linear
    lever can also reverse the direction of movement, and can be used
       travel. for a fluid seal
   Rotary The actuator is connected to a rotary ♦High
 mechanical advantage ♦Complex construction ♦I
  J28
   impeller impeller. A small angular deflection ♦The ratio
   of force to travel ♦Unsuitable for pigmented inks
          of the actuator results in a rotation of of the actuator can be
    the impeller vanes, which push the matched to the nozzle
    ink against stationary vanes and out requirements by varying the
        of the nozzle. number of impeller vanes
   Acoustic lens A refractive or diffractive (e.g. zone ♦No
   moving parts ♦Large area required ♦1993
 Hadimioglu et
    plate) acoustic lens is used to  ♦Only relevant for
 acoustic ink jets al, EUP 550, 192
    concentrate sound waves.   ♦1993 Elrod et al, EUP
            572,220
   Sharp A sharp point is used to concentrate ♦Simple
 construction ♦Difficult to fabricate using standard
 ♦Tone-jet
   conductive an electrostatic field.  VLSL processes for a surface
 ejecting
   point   ink-jet
      ♦Only relevant for electrostatic ink jets
   ACTUATOR MOTION
   Actuator
   motion
   Volume The volume of the actuator changes, ♦Simple
 construction in the ♦High energy is typically required to
 ♦Hewlett-Packard
   expansion pushing the ink in all directions. case of thermal ink jet
 achieve volume expansion. This leads Thermal Inkjet
      to thermal stress, cavitation, and ♦Canon Bubblejet
       kogation in thermal ink jet
      implementations
   Linear, normal The actuator moves in a direction ♦Efficie
  nt coupling to ink ♦High fabrication complexity may be
 ♦IJ01, IJ02, IJ04, IJ07
   to chip surface normal to the print head surface. The drops ejected
 normal to the required to achieve perpendicular ♦IJ11,
 IJ14
    nozzle is typically in the line of surface motion
    movement.
   Linear, parallel The actuator moves parallel to the ♦Suit
  able for planar ♦Fabrication complexity ♦IJ1
  2, IJ13, IJ15, IJ33,
   to chip surface print head surface. Drop ejection fabrication
 ♦Friction ♦IJ34, IJ35, IJ36
    may still be normal to the surface.  ♦Stiction
   Membrane An actuator with a high force but ♦The effective
   area of the ♦Fabrication complexity ♦1982
 Hawkins U.S. Pat. No.
   push small area is used to push a stiff actuator becomes the .diamond-s
  olid.Actuator size 4,459,601
    membrane that is in contact with the membrane area ♦Diff
  iculty of integration in a VLSI
    ink.  process
   Rotary The actuator causes the rotation of ♦Rotary
 levers may be used ♦Device complexity ♦IJ05,
   IJ08, IJ13, IJ28
    some element, such a grill or to increase travel ♦May
 have friction at a pivot point
    impeller ♦Small chip area
     requirements
   Bend The actuator bends when energized. ♦A very small
 change in ♦Requires the actuator to be made from .diamond-s
  olid.1970 Kyser et al U.S. Pat. No.
    This may be due to differential dimensions can be at least two
 distinct layers, or to have a 3,946,398
    thermal expansion, piezoelectric converted to a large motion. thermal
   difference across the actuator ♦1973 Stemme U.S. Pat.
 No.
    expansion, magnetostriction, or other   ♦3,747,120
        form of relative dimensional change.   ♦IJ03, IJ09,
   IJ10, IJ19
       ♦IJ23, IJ24, IJ25, IJ29
       ♦IJ30, IJ31, IJ33, IJ34
       ♦IJ35
   Swivel The actuator swivels around a central ♦Allows
 operation where the ♦Inefficient coupling to the ink
 motion ♦IJ06
    pivot. This motion is suitable where net linear force on the
    there are opposite forces applied to paddle is zero
    opposite sides of the paddle, e.g. ♦Small chip area
       Lorenz force. requirements
   Straighten The actuator is normally bent, and ♦Can be
 used with shape ♦Requires careful balance of stresses to
 ♦IJ26, IJ32
    straightens when energized. memory alloys where the ensure that the
 quiescent bend is
     austenic phase is planar accurate
   Double bend The actuator bends in one direction ♦One
 actuator can be used to ♦Difficult to make the drops
 ejected by ♦IJ36, IJ37, IJ38
    when one element is energized, and power two nozzles. both bend
 directions identical.
    bends the other way when another ♦Reduced chip size.
 ♦A small efficiency loss compared to
    element is energized. ♦Not sensitive to ambient
 equivalent single bend actuators.
     temperature
   Shear Energizing the actuator causes a ♦Can increase the
   effective ♦Not readily applicable to other actuator
 ♦1985 Fishbeck U.S. Pat. No.
    shear motion in the actuator material. travel of piezoelectric
 mechanisms 4,584,590
     actuators
   Radial The actuator squeezes an ink ♦Relatively easy to
 fabricate ♦High force required ♦1970 Zoltan
 U.S. Pat. No.
   constriction reservoir, forcing ink from a single nozzles from glass
 ♦Inefficient 3,683,212
    constricted nozzle. tubing as macroscopic ♦Difficult to
   integrate with VLSI
     structures processes
   Coil/uncoil A coiled actuator uncoils or coils ♦Easy to
 fabricate as a planar ♦Difficult to fabricate for non-plana
  r ♦IJ17, IJ21, IJ34, IJ35
    more tightly. The motion of the free VLSI process devices
    end of the actuator ejects the ink. ♦Small area
 required, ♦Poor out-of-plane stiffness
     therefore low cost
   Bow The actuator bows (or buckles) in the ♦Can increase
 the speed of ♦Maximum travel is constrained ♦
  IJ16, IJ18, IJ27
    middle when energized. travel ♦High force required
         ♦Mechanically rigid
   Push-Pull Two actuators control a shutter. One ♦The
 structure is pinned at ♦Not readily suitable for inkjets
 which ♦IJ18
    actuator pulls the shutter, and the both ends, so has a high directly
   push the ink
    other pushes it. out-of-plane rigidity
   Curl inwards A set of actuators curl inwards to ♦Good
 fluid flow to the ♦Design complexity ♦IJ20,
 IJ42
    reduce the volume of ink that they region behind the actuator
           enclose. increases efficiency
   Curl outwards A set of actuators curl outwards, ♦Relative
  ly simple ♦Relatively large chip area ♦IJ43
    pressurizing ink in a chamber construction
    surrounding the actuators, and
    expelling ink from a nozzle in the
    chamber.
   Iris Multiple vanes enclose a volume of ♦High efficiency
   ♦High fabrication complexity ♦IJ22
           ink. These simultaneously rotate, ♦Small chip
 area ♦Not suitable for pigmented inks
    reducing the volume between the
    vanes.
   Acoustic The actuator vibrates at a high ♦The actuator
 can be ♦Large area required for efficient ♦19
  93 Hadimioglu et
   vibration frequency. physically distant from the operation at useful
 frequencies al, EUP 550,192
     ink ♦Acoustic coupling and crosstalk ♦199
  3 Elrod et al, EUP
      ♦Complex drive circuitry. 572,220
      ♦Poor control of drop volume and
      position
   None In various ink jet designs the actuator ♦No moving
 parts ♦Various other tradeoffs are required to .diamond-sol
  id.Silverbrook, EP 0771
    does not move.  eliminate moving parts 658 A2 and related
       patent applications
       ♦Tone-jet
   NOZZLE REFILL METHOD
   Nozzle refill
   method
   Surface After the actuator is energized, it ♦Fabrication
   simplicity ♦Low speed ♦Thermal inkjet
       tension typically returns rapidly to its normal ♦Oper
  ational simplicity ♦Surface tension force relatively
 small ♦Piezoelectric inkjet
    position. This rapid return sucks in  compared to actuator force
 ♦IJ01-IJ07, IJ10-IJ14
    air through the nozzle opening. The  ♦Long refill time
 usually dominates the ♦IJ16, IJ20, IJ22-IJ45
    ink surface tension at the nozzle then  total repetition rate
           exerts a small force restoring the
    meniscus to a minimum area.
   Shuttered Ink to the nozzle chamber is ♦High speed
 ♦Requires common ink pressure ♦IJ08, IJ13,
 IJ15, IJ17
   oscillating ink provided at a pressure that oscillates ♦L
  ow actuator energy, as the oscillator ♦IJ18, IJ19, IJ21
    pressure at twice the drop ejection frequency. actuator need only
 open or ♦May not be suitable for pigmented inks
    When a drop is to be ejected, the close the shutter, instead of
         shutter is opened for 3 half cycles: ejecting the ink drop
         drop ejection, actuator return, and
    refill.
   Refill actuator After the main actuator has ejected a ♦Hi
  gh speed, as the nozzle is ♦Requires two independent
 actuators per ♦IJ09
    drop a second (refill) actuator is actively refilled nozzle
    energized. The refill actuator pushes
    ink into the nozzle chamber. The
    refill actuator returns slowly, to
    prevent its return from emptying the
    chamber again.
   Positive ink The ink is held a slight positive ♦High
 refill rate, therefore a ♦Surface spill must be prevented
 ♦Silverbrook, EP 0771
   pressure pressure. After the ink drop is high drop repetition rate is
 ♦Highly hydrophobic print head 658 A2 and related
    ejected, the nozzle chamber fills possible surfaces are required
 patent applications
    quickly as surface tension and ink   ♦Alternative for:
    pressure both operate to refill the   ♦IJ01-IJ07,
 IJ10-IJ14
    nozzle.   ♦IJ16, IJ20, IJ22-IJ45
   METHOD OF RESTRICTING BACK-FLOW THROUGH INLET
   Inlet back-flow
   restriction
   method
   Long inlet The ink inlet channel to the nozzle ♦Design
 simplicity ♦Restricts refill rate ♦Thermal
 inkjet
   channel chamber is made long and relatively ♦Operational
   simplicity ♦May result in a relatively large chip
 ♦Piezoelectric inkjet
    narrow, relying on viscous drag to ♦Reduces crosstalk
 area ♦IJ42, IJ43
    reduce inlet back-flow.  ♦Only partially effective
       Positive ink The ink is under a positive pressure, ♦D
  rop selection and ♦Requires a method (such as a nozzle
 ♦Silverbrook, EP 0771
   pressure so that in the quiescent state some of separation forces can
 be rim or effective hydrophobizing, or 658 A2 and related
    the ink drop already protrudes from reduced both) to prevent flooding
   of the patent applications
    the nozzle. ♦Fast refill time ejection surface of the
 print head. ♦possible operation of
    This reduces the pressure in the   the following:
    nozzle chamber which is required to   ♦IJ01-IJ07,
 IJ09-IJ12
    eject a certain volume of ink. The   ♦IJ14, IJ16, IJ20,
   IJ22,
    reduction in chamber pressure results   ♦IJ23-IJ34,
 IJ36-IJ41
    in a reduction in ink pushed out   ♦IJ44
    through the inlet.
   Baffle One or more baffles are placed in the ♦The refill
   rate is not as ♦Design complexity ♦HP
 Thermal Ink Jet
    inlet ink flow. When the actuator is restricted as the long inlet
 ♦May increase fabrication complexity ♦Tektron
  ix
    energized, the rapid ink movement method. (e.g. Tektronix hot melt
 Piezoelectric piezoelectric ink jet
    creates eddies which restrict the flow ♦Reduces
 crosstalk print heads).
    through the inlet. The slower refill
    process is unrestricted, and does not
    result in eddies.
   Flexible flap In this method recently disclosed by ♦Signi
  ficantly reduces back- ♦Not applicable to most inkjet
 ♦Canon
   restricts inlet Canon, the expanding actuator flow for edge-shooter
 configurations
    (bubble) pushes on a flexible flap thermal ink jet devices .diamond-so
  lid.Increased fabrication complexity
    that restricts the inlet.  ♦Inelastic deformation of
 polymer flap
      results in creep over extended use
   Inlet filter A filter is located between the ink ♦Additio
  nal advantage of ink ♦Restricts refill rate .diamond-solid
  .IJ04, IJ12, IJ24,
    inlet and the nozzle chamber. The filtration ♦May
 result in complex construction ♦IJ29, IJ30
    filter has a multitude of small holes ♦Ink filter may
 be fabricated
    or slots, restricting ink flow. The with no additional process
          filter also removes particles which steps
    may block the nozzle.
   Small inlet The ink inlet channel to the nozzle ♦Design
 simplicity ♦Restricts refill rate ♦IJ02,
 IJ37, IJ44
   compared to chamber has a substantially smaller  ♦May
 result in a relatively large chip
   nozzle cross section than that of the nozzle,  area
    resulting in easier ink egress out of  ♦Only partially
 effective
    the nozzle than out of the inlet.
   Inlet shutter A secondary actuator controls the ♦Increase
  s speed of the ink- ♦Requires separate refill actuator
 and ♦IJ09
    position of a shutter, closing off the jet print head operation drive
   circuit
    ink inlet when the main actuator is
    energized.
   The inlet is The method avoids the problem of ♦Back-flow
   problem is ♦Requires careful design to minimize .diamond-
  solid.IJ01, IJ03, IJ05, IJ06
   located behind inlet back-flow by arranging the ink- eliminated the
 negative pressure behind the paddle ♦IJ07, IJ10, IJ11,
 IJ14
   the ink- pushing surface of the actuator   ♦IJ16, IJ22,
 IJ23, IJ25
   pushing between the inlet and the nozzle.   ♦IJ28, IJ31,
   IJ32, IJ33
   surface    ♦IJ34, IJ35, IJ36, IJ39
       ♦IJ40, IJ41
   Part of the The actuator and a wall of the ink ♦Significa
  nt reductions in ♦Small increase in fabrication .diamond-s
  olid.IJ07, IJ20, IJ26, IJ38
   actuator chamber are arranged so that the back-flow can be achieved
 complexity
   moves to shut motion of the actuator closes off the ♦Comp
  act designs possible
   off the inlet inlet.
   Nozzle In some configurations of ink jet, ♦Ink back-flow
   problem is ♦None related to ink back-flow on .diamond-sol
  id.Silverbrook, EP 0771
   actuator does there is no expansion or movement eliminated actuation
 658 A2 and related
   not result in of an actuator which may cause ink   patent applications
   ink back-flow back-flow through the inlet.   ♦Valve-jet
       ♦Tone-jet
       ♦IJ08, IJ13, IJ15, IJ17
       ♦IJ18, IJ19, IJ21
   NOZZLE CLEARING METHOD
   Nozzle
   Clearing
   method
   Normal nozzle All of the nozzles are fired ♦No added
 complexity on the ♦May not be sufficient to displace dried
   ♦Most ink jet systems
   firing periodically, before the ink has a print head ink .diamond-solid
  .IJ01-IJ07, IJ09-IJ12
    chance to dry. When not in use the   ♦IJ14, IJ16, IJ20,
   IJ22
    nozzles are sealed (capped) against   ♦IJ23-IJ34,
 IJ36-IJ45
    air.
    The nozzle firing is usually
    performed during a special clearing
    cycle, after first moving the print
    head to a cleaning station.
   Extra power to In systems which heat the ink, but do ♦Can
   be highly effective if ♦Requires higher drive voltage
 for ♦Silverbrook, EP 0771
   ink heater not boil it under normal situations, the heater is adjacent
   to the clearing 658 A2 and related
    nozzle clearing can be achieved by nozzle ♦May require
 larger drive transistors patent applications
    over-powering the heater and boiling
    ink at the nozzle.
   Rapid The actuator is fired in rapid ♦Does not require
 extra drive ♦Effectiveness depends substantially .diamond-s
  olid.May be used with:
   succession of succession. In some configurations, circuits on the
 print head upon the configuration of the inkjet ♦IJ01-IJ07,
   IJ09-IJ11
   actuator this may cause heat build-up at the ♦Can be
 readily controlled nozzle ♦IJ14, IJ16, IJ20, IJ22
   pulses nozzle which boils the ink, clearing and initiated by digital
 logic  ♦IJ23-1125, IJ27-IJ34
    the nozzle. In other situations, it may   ♦IJ36-IJ45
      cause sufficient vibrations to
    dislodge clogged nozzles.
   Extra power to Where an actuator is not normally ♦A
 simple solution where ♦Not suitable where there is a hard
 limit ♦May be used with:
   ink pushing driven to the limit of its motion, applicable to actuator
 movement ♦IJ03, IJ09, IJ16, IJ20
   actuator nozzle clearing may be assisted by   ♦IJ23,
 IJ24, IJ25, IJ27
    providing an enhanced drive signal   ♦IJ29, IJ30, IJ31,
   IJ32
    to the actuator.   ♦IJ39, IJ40, IJ41, IJ42
       ♦IJ43, IJ44, IJ45
   Acoustic An ultrasonic wave is applied to the ♦A high
 nozzle clearing ♦High implementation cost if system
 ♦IJ08, IJ13, IJ15, IJ17
   resonance ink chamber. This wave is of an capability can be achieved
 does not already include an acoustic ♦IJ18, IJ19, IJ21
       appropriate amplitude and frequency ♦May be implement
  ed at actuator
    to cause sufficient force at the nozzle very low cost in systems
        to clear blockages. This is easiest to which already include
        achieve if the ultrasonic wave is at a acoustic actuators
           resonant frequency of the ink cavity.
   Nozzle A microfabricated plate is pushed ♦Can clear
 severely clogged ♦Accurate mechanical alignment is
 ♦Silverbrook, EP 0771
   clearing plate against the nozzles. The plate has a nozzles required
 658 A2 and related
    post for every nozzle. The array of  ♦Moving parts are
 required patent applications
    posts  ♦There is risk of damage to the nozzles
      ♦Accurate fabrication is required
   Ink pressure The pressure of the ink is ♦May be effective
   where ♦Requires pressure pump or other ♦May
   be used with all
   pulse temporarily increased so that ink other methods cannot be
 pressure actuator IJ series ink
    streams from all of the nozzles. This used ♦Expensive
     may be used in conjunction with  ♦Wasteful of ink
        actuator energizing.
   Print head A flexible `blade`
  is wiped across the ♦Effective for planar print .diamond-s
  olid.Difficult to use if print head surface is ♦Many ink
 jet systems
   wiper print head surface. The blade is head surfaces non-planar or
 very fragile
    usually fabricated from a flexible ♦Low cost .diamond-so
  lid.Requires mechanical parts
    polymer, e.g. rubber or synthetic  ♦Blade can wear out
 in high volume
    elastomer.  print systems
   Separate ink A separate heater is provided at the ♦Can
 be effective where ♦Fabrication complexity ♦C
  an be used with
   boiling heater nozzle although the normal drop e- other nozzle
 clearing  many IJ series ink
    ection mechanism does not require it. methods cannot be used  jets
      The heaters do not require individual ♦Can be
 implemented at no
    drive circuits, as many nozzles can additional cost in some
    be cleared simultaneously, and no inkjet configurations
    imaging is required.
   NOZZLE PLATE CONSTRUCTION
   Nozzle plate
   construction
   Electroformed A nozzle plate is separately ♦Fabrication
 simplicity ♦High temperatures and pressures are .diamond-so
  lid.Hewlett Packard
   nickel fabricated from electroformed nickel,  required to bond nozzle
 plate Thermal Inkjet
    and bonded to the print head chip.  ♦Minimum thickness
 constraints
      ♦Differential thermal expansion
   Laser ablated Individual nozzle holes are ablated ♦No
 masks required ♦Each hole must be individually formed
 ♦Canon Bubblejet
   or drilled by an intense UV laser in a nozzle ♦Can be
 quite fast ♦Special equipment required ♦1988
   Sercel et al.,
   polymer plate, which is typically a polymer ♦Some
 control over nozzle ♦Slow where there are many thousands
 SPIE, Vol. 998
    such as polyimide or polysulphone profile is possible of nozzles per
 print head Excimer Beam
     ♦Equipment required is ♦May produce thin
   burrs at exit holes Applications, pp. 76-
     relatively low cost  83
       ♦1993 Watanabe et al.,
       U.S. Pat. No. 5,208,604
   Silicon micro- A separate nozzle plate is ♦High accuracy
   is attainable ♦Two part construction ♦K.
 Bean, IEEE
   machined micromachined from single crystal  ♦High cost
 Transactions on
    silicon, and bonded to the print head  ♦Requires
 precision alignment Electron Devices,
    wafer.  ♦Nozzles may be clogged by adhesive Vol. ED-25,
   No. 10,
       1978, pp 1185-1195
       ♦Xerox 1990 Hawkin
       et al., U.S. Pat. No. 4,899,181
   Glass Fine glass capillaries are drawn from ♦No expensive
   equipment ♦Very small nozzle sizes are difficult to
 ♦1970 Zoltan U.S. Pat. No.
   capillaries glass tubing. This method has been required form 3,683,212
    used for making individual nozzles, ♦Simple to make
 single ♦Not suited for mass production
    but is difficult to use for bulk nozzles
    manufacturing of print heads with
    thousands of nozzles.
   Monolithic, The nozzle plate is deposited as a ♦High
 accuracy (&lt;1 μm) ♦Requires sacrificial layer under the
 ♦Silverbrook, EP 0771
   surface micro- layer using standard VLSI deposition ♦Mono
  lithic nozzle plate to form the nozzle 658 A2 and related
   machined techniques. Nozzles are etched in the ♦Low cost
   chamber patent applications
   using VLSI nozzle plate using VLSI lithography ♦Existing
   processes can be ♦Surface may be fragile to the touch
 ♦IJ01, IJ02, IJ04, IJ11
   lithographic and etching. used  ♦IJ12, IJ17, IJ18, IJ20
   processes    ♦IJ22, IJ24, IJ27, IJ28
       ♦IJ29, IJ30, IJ31, IJ32
       ♦IJ33, IJ34, IJ36, IJ37
       ♦IJ38, IJ39, IJ40, IJ41
       ♦IJ42, IJ43, IJ44
   Monolithic, The nozzle plate is a buried etch stop ♦High
   accuracy (&lt;1 μm) ♦Requires long etch times .diamond-so
  lid.IJ03, IJ05, IJ06, IJ07
   etched in the wafer. Nozzle chambers are ♦Monolithic
 ♦Requires a support wafer ♦IJ08, IJ09, IJ10,
   IJ13
   through etched in the front of the wafer, and ♦Low cost
   ♦IJ14, IJ15, IJ16, IJ19
   substrate the wafer is thinned from the back ♦No
 differential expansion  ♦IJ21, IJ23, IJ25, IJ26
    side. Nozzles are then etched in the
    etch stop layer.
   No nozzle Various methods have been tried to ♦No nozzles
   to become ♦Difficult to control drop position .diamond-so
  lid.Ricoh 1995 Sekiya et
   plate eliminate the nozzles entirely, to clogged accurately al U.S.
 Pat. No. 5,412,413
    prevent nozzle clogging. These  ♦Crosstalk problems
 ♦1993 Hadimioglu et
    include thermal bubble mechanisms   al EUP 550,192
    and acoustic lens mechanisms   ♦1993 Elrod et al EUP
         572,220
   Trough Each drop ejector has a trough ♦Reduced manufactur
  ing ♦Drop firing direction is sensitive to ♦
  IJ35
    through which a paddle moves. complexity wicking.
    There is no nozzle plate. ♦Monolithic
   Nozzle slit The elimination of nozzle holes and ♦No
 nozzles to become ♦Difficult to control drop position
 ♦1989 Saito et al U.S. Pat. No.
   instead of replacement by a slit encompassing clogged accurately
 4,799,068
   individual many actuator positions reduces  ♦Crosstalk
 problems
   nozzles nozzle clogging, but increases
    crosstalk due to ink surface waves
   DROP EJECTION DIRECTION
   Ejection
   direction
   Edge Ink flow is along the surface of the ♦Simple
 construction ♦Nozzles limited to edge ♦Canon
   Bubblejet
   (`edge chip, and ink drops are ejected from ♦No silicon
 etching required ♦High resolution is difficult 1979 Endo
 et al GB
   shooter`) the chip edge. ♦Good heat sinking via .diamond-
  solid.Fast color printing requires one print patent 2,007,162
     ♦substrate head per color ♦Xerox
 heater-in-pit
     ♦Mechanically strong  1990 Hawkins et al
     ♦Ease of chip handing  U.S. Pat. No. 4,899,181
              ♦Tone-jet
   Surface Ink flow is along the surface of the ♦No bulk
 silicon etching ♦Maximum ink flow is severely .diamond-soli
  d.Hewlett-Packard TIJ
   (`roof shooter`) chip, and ink drops are ejected from required
 restricted 1982 Vaught et al
    the chip surface, normal to the plane ♦Silicon can make
   an  U.S. Pat. No. 4,490,728
    of the chip. effective heat sink  ♦IJ02, IJ11, IJ12,
 IJ20
     ♦Mechanical strength  ♦IJ22
   Through chip, Ink flow is through the chip, and ink ♦High
   ink flow ♦Requires bulk silicon etching ♦Si
  lverbrook, EP 0771
   forward drops are ejected from the front ♦Suitable for
 pagewidth print  658 A2 and related
   (`up shooter`) surface of the chip. ♦High nozzle packing
    patent applications
     density therefore low  ♦IJ04, IJ17, IJ18, IJ24
            manufacturing cost  ♦IJ27-IJ45
   Through chip, Ink flow is through the chip, and ink ♦High
   ink flow ♦Requires wafer thinning ♦IJ01,
 IJ03, IJ05, IJ06
   reverse drops are ejected from the rear ♦Suitable for
 pagewidth print ♦Requires special handling during .diamond-
  solid.IJ07, IJ08, IJ09, IJ10
   (`down surface of the chip. ♦High nozzle packing
 manufacture ♦IJ13, IJ14, IJ15, IJ16
   shooter`)  density therefore low  ♦IJ19, IJ21, IJ23,
 IJ25
     manufacturing cost  ♦IJ26
   Through Ink flow is through the actuator, ♦Suitable for
 piezoelectric ♦Pagewidth print heads require several
 ♦Epson Stylus
   actuator which is not fabricated as part of the print heads thousand
 connections to drive circuits ♦Tektronix hot melt
    same substrate as the drive  ♦Cannot be manufactured in
   standard piezoelectric ink jets
    transistors.  CMOS fabs
      ♦Complex assembly required
   INK TYPE
   Ink type
   Aqueous, dye Water based ink which typically ♦Environment
  ally friendly ♦Slow drying ♦Most existing
 inkjets
    contains: water, dye, surfactant, ♦No odor .diamond-soli
  d.Corrosive ♦All IJ series ink jets
    humectant, and biocide.  ♦Bleeds on paper .diamond-solid
  .Silverbrook, EP 0771
    Modern ink dyes have high water-  ♦May strikethrough
 658 A2 and related
    fastness, light fastness  ♦Cockles paper patent
 applications
   Aqueous, Water based ink which typically ♦Environmentally
   friendly ♦Slow drying ♦IJ02, IJ04, IJ21,
 IJ26
   pigment contains: water, pigment, surfactant, ♦No odor
 ♦Corrosive ♦IJ27, IJ30
    humectant, and biocide. ♦Reduced bleed ♦Pi
  gment may clog nozzles ♦Silverbrook, EP 0771
    Pigments have an advantage in ♦Reduced wicking .diamond-
  solid.Pigment may clog actuator 658 A2 and related
    reduced bleed, wicking and ♦Reduced strikethrough
 mechanisms patent applications
    strikethrough.  ♦Cockles paper ♦Piezoelect
  ric ink-jets
       ♦Thermal ink jets
       (with significant
       restrictions)
   Methyl Ethyl MEK is a highly volatile solvent ♦Very fast
   drying ♦Odorous ♦All IJ series ink jets
     Ketone (MEK) used for industrial printing on ♦Prints
 on various substrates ♦Flammable
    difficult surfaces such as aluminum such as metals and plastics
         cans.
   Alcohol Alcohol based inks can be used ♦Fast drying
 ♦Slight odor ♦All IJ series ink jets
          (ethanol, 2- where the printer must operate at ♦Op
  erates at sub-freezing ♦Flammable
   butanol, and temperatures below the freezing temperatures
   others) point of water. An example of this is ♦Reduced
 paper cockle
    in-camera consumer photographic ♦Low cost
    printing.
   Phase change The ink is solid at room temperature, ♦No
 drying time-ink ♦High viscosity ♦Tektronix
 hot melt
   (hot melt) and is melted in the print head before instantly freezes on
   the ♦Printed ink typically has a `waxy`
  feel piezoelectric ink jets
    jetting. Hot melt inks are usually print medium ♦Printed
   pages may `block` ♦1989 Nowak U.S. Pat. No.
    wax based, with a melting point ♦Almost any print
 medium ♦Ink temperature may be above the 4,820,346
           around 80° C. After jetting the ink can be used curie
 point of permanent magnets ♦All IJ series ink jets
           freezes almost instantly upon ♦No paper cockle
 occurs ♦Ink heaters consume power
    contacting the print medium or a ♦No wicking occurs
 ♦Long warm-up time
    transfer roller. ♦No bleed occurs
     ♦No strikethrough occurs
   Oil Oil based inks are extensively used ♦High solubility
   medium for ♦High viscosity: this is a significant
 ♦All IJ series ink jets
    in offset printing. They have some dyes limitation for use in
 inkjets, which
    advantages in improved ♦Does not cockle paper usually
 require a low viscosity. Some
    characteristics on paper (especially ♦Does not wick
 through short chain and multi-branched oils
    no wicking or cockle.). Oil soluble paper have a sufficiently low
 viscosity.
    dies and pigments are required.  ♦Slow drying
   Microemulsion A microemulsion is a stable, self ♦Stops
 ink bleed ♦Viscosity higher than water ♦All
 IJ series ink jets
    forming emulsion of oil, water, and ♦High dye solubility
   ♦Cost is slightly higher than water based
    surfactant. The characteristic drop ♦Water, oil, and
 amphiphilic ink
    size is less than 100 nm, and is soluble dies can be used .diamond-sol
  id.High surfactant concentration required
    determined by the preferred ♦Can stabilize pigment
 (around 5%)
    curvature of the surfactant. suspensions
 
    
     Ink Jet Printing 
     A large number of new forms of ink jet printers have been developed to facilitate alternative ink jet technologies for the image processing and data distribution system. Various combinations of ink jet devices can be included in printer devices incorporated as part of the present invention. Australian Provisional Patent Applications relating to these ink jets which are specifically incorporated by cross reference include: 
     
         __________________________________________________________________________
Australian                                                                
                Provisional                                               
  Number Filing Date Title                                                
__________________________________________________________________________
PO8066  Jul-15-97                                                         
               Image Creation Method and Apparatus (IJ01)                 
  PO8072 Jul-15-97 Image Creation Method and Apparatus (IJ02)             
  PO8040 Jul-15-97 Image Creation Method and Apparatus (IJ03)             
  PO8071 Jul-15-97 Image Creation Method and Apparatus (IJ04)             
  PO8047 Jul-15-97 Image Creation Method and Apparatus (IJ05)             
  PO8035 Jul-15-97 Image Creation Method and Apparatus (IJ06)             
  PO8044 Jul-15-97 Image Creation Method and Apparatus (IJ07)             
  PO8063 Jul-15-97 Image Creation Method and Apparatus (IJ08)             
  PO8057 Jul-15-97 Image Creation Method and Apparatus (IJ09)             
  PO8056 Jul-15-97 Image Creation Method and Apparatus (IJ10)             
  PO8069 Jul-15-97 Image Creation Method and Apparatus (IJ11)             
  PO8049 Jul-15-97 Image Creation Method and Apparatus (IJ12)             
  PO8036 Jul-15-97 Image Creation Method and Apparatus (IJ13)             
  PO8048 Jul-15-97 Image Creation Method and Apparatus (IJ14)             
  PO8070 Jul-15-97 Image Creation Method and Apparatus (IJ15)             
  PO8067 Jul-15-97 Image Creation Method and Apparatus (IJ16)             
  PO8001 Jul-15-97 Image Creation Method and Apparatus (IJ17)             
  PO8038 Jul-15-97 Image Creation Method and Apparatus (IJ18)             
  PO8033 Jul-15-97 Image Creation Method and Apparatus (IJ19)             
  PO8002 Jul-15-97 Image Creation Method and Apparatus (IJ20)             
  PO8068 Jul-15-97 Image Creation Method and Apparatus (IJ21)             
  PO8062 Jul-15-97 Image Creation Method and Apparatus (IJ22)             
  PO8034 Jul-15-97 Image Creation Method and Apparatus (IJ23)             
  PO8039 Jul-15-97 Image Creation Method and Apparatus (IJ24)             
  PO8041 Jul-15-97 Image Creation Method and Apparatus (IJ25)             
  PO8004 Jul-15-97 Image Creation Method and Apparatus (IJ26)             
  PO8037 Jul-15-97 Image Creation Method and Apparatus (IJ27)             
  PO8043 Jul-15-97 Image Creation Method and Apparatus (IJ28)             
  PO8042 Jul-15-97 Image Creation Method and Apparatus (IJ29)             
  PO8064 Jul-15-97 Image Creation Method and Apparatus (IJ30)             
  PO9389 Sep-23-97 Image Creation Method and Apparatus (IJ31)             
  PO9391 Sep-23-97 Image Creation Method and Apparatus (IJ32)             
  PP0888 Dec-12-97 Image Creation Method and Apparatus (IJ33)             
  PP0891 Dec-12-97 Image Creation Method and Apparatus (IJ34)             
  PP0890 Dec-12-97 Image Creation Method and Apparatus (IJ35)             
  PP0873 Dec-12-97 Image Creation Method and Apparatus (IJ36)             
  PP0993 Dec-12-97 Image Creation Method and Apparatus (IJ37)             
  PP0890 Dec-12-97 Image Creation Method and Apparatus (IJ38)             
  PP1398 Jan-19-98 An Image Creation Method and Apparatus (IJ39)          
  PP2592 Mar-25-98 An Image Creation Method and Apparatus (IJ40)          
  PP2593 Mar-25-98 Image Creation Method and Apparatus (IJ41)             
  PP3991 Jun-9-98 Image Creation Method and Apparatus (IJ42)              
  PP3987 Jun-9-98 Image Creation Method and Apparatus (IJ43)              
  PP3985 Jun-9-98 Image Creation Method and Apparatus (IJ44)              
  PP3983 Jun-9-98 Image Creation Method and Apparatus (IJ45)              
__________________________________________________________________________
 
    
     Ink Jet Manufacturing 
     Further, the present application may utilize advanced semiconductor fabrication techniques in the construction of large arrays of ink jet printers. Suitable manufacturing techniques are described in the following Australian provisional patent specifications incorporated here by cross-reference: 
     
         __________________________________________________________________________
Australian Provisional                                                    
  Number Filing Date Title                                                
__________________________________________________________________________
PO7935    15-Jul-97                                                       
                A Method of Manufacture of an Image Creation Apparatus    
                (IJM01)                                                   
  PO7936 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus 
                (IJM02)                                                   
  PO7937 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus 
                (IJM03)                                                   
  PO8061 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus 
                (IJM04)                                                   
  PO8054 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus 
                (IJM05)                                                   
  PO8065 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus 
                (IJM06)                                                   
  PO8055 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus 
                (IJM07)                                                   
  PO8053 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus 
                (IJM08)                                                   
  PO8078 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus 
                (IJM09)                                                   
  PO7933 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus 
                (IJM10)                                                   
  PO7950 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus 
                (IJM11)                                                   
  PO7949 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus 
                (IJM12)                                                   
  PO8060 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus 
                (IJM13)                                                   
  PO8059 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus 
                (IJM14)                                                   
  PO8073 15-Jul-91 A Method of Manufacture of an Image Creation Apparatus 
                (IJM15)                                                   
  PO8076 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus 
                (IJM16)                                                   
  PO8075 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus 
                (IJM17)                                                   
  PO8079 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus 
                (IJM18)                                                   
  PO8050 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus 
                (IJM19)                                                   
  PO8052 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus 
                (IJM20)                                                   
  PO7948 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus 
                (IJM21)                                                   
  PO7951 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus 
                (IJM22)                                                   
  PO8074 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus 
                (IJM23)                                                   
  PO7941 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus 
                (IJM24)                                                   
  PO8077 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus 
                (IJM25)                                                   
  PO8058 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus 
                (IJM26)                                                   
  PO8051 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus 
                (IJM27)                                                   
  PO8045 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus 
                (IJM28)                                                   
  PO7952 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus 
                (IJM29)                                                   
  PO8046 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus 
                (IJM30)                                                   
  PO8503 11-Aug-97 A Method of Manufacture of an Image Creation Apparatus 
                (IJM30a)                                                  
  PO9390 23-Sep-97 A Method of Manufacture of an Image Creation Apparatus 
                (IJM31)                                                   
  PO9392 23-Sep-97 A Method of Manufacture of an Image Creation Apparatus 
                (IJM32)                                                   
  PP0889 12-Dec-97 A Method of Manufacture of an Image Creation Apparatus 
                (IJM35)                                                   
  PP0887 12-Dec-97 A Method of Manufacture of an Image Creation Apparatus 
                (IJM36)                                                   
  PP0882 12-Dec-97 A Method of Manufacture of an Image Creation Apparatus 
                (IJM37)                                                   
  PP0874 12-Dec-97 A Method of Manufacture of an Image Creation Apparatus 
                (IJM38)                                                   
  PP1396 19-Jan-98 A Method of Manufacture of an Image Creation Apparatus 
                (IJM39)                                                   
  PP2591 25-Mar-98 A Method of Manufacture of an Image Creation Apparatus 
                (IJM41)                                                   
  PP3989 9-Jun-98 A Method of Manufacture of an Image Creation Apparatus  
                (IJM40)                                                   
  PP3990 9-Jun-98 A Method of Manufacture of an Image Creation Apparatus  
                (IJM42)                                                   
  PP3986 9-Jun-98 A Method of Manufacture of an Image Creation Apparatus  
                (IJM43)                                                   
  PP3984 9-Jun-98 A Method of Manufacture of an Image Creation Apparatus  
                (IJM44)                                                   
  PP3982 9-Jun-98 A Method of Manufacture of an Image Creation Apparatus  
                (IJM45)                                                   
__________________________________________________________________________
 
    
     Fluid Supply 
     Further, the present application may utilize an ink delivery system to the ink jet head. Delivery systems relating to the supply of ink to a series of ink jet nozzles are described in the following Australian provisional patent specifications, the disclosure of which are hereby incorporated by cross-reference: 
     
         ______________________________________                                    
Australian                                                                
  Provisional                                                             
  Number Filing Date Title                                                
______________________________________                                    
PO8003    15-Jul-97  Supply Method and Apparatus (F1)                     
  PO8005 15-Jul-97 Supply Method and Apparatus (F2)                       
  PO9404 23-Sep-97 A Device and Method (F3)                               
______________________________________                                    
 
    
     MEMS Technology 
     Further, the present application may utilize advanced semiconductor microelectromechanical techniques in the 10 construction of large arrays of ink jet printers. Suitable microelectromechanical techniques are described in the following Australian provisional patent specifications incorporated here by cross-reference: 
     
         ______________________________________                                    
Australian                                                                
  Provisional                                                             
  Number Filing Date Title                                                
______________________________________                                    
PO7943    15-Jul-97  A device (MEMS01)                                    
  PO8006 15-Jul-97 A device (MEMS02)                                      
  PO8007 15-Jul-97 A device (MEMS03)                                      
  PO8008 15-Jul-97 A device (MEMS04)                                      
  PO8010 15-Jul-97 A device (MEMS05)                                      
  PO8011 15-Jul-97 A device (MEMS06)                                      
  PO7947 15-Jul-97 A device (MEMS07)                                      
  PO7945 15-Jul-97 A device (MEMS08)                                      
  PO7944 15-Jul-97 A device (MEMS09)                                      
  PO7946 15-Jul-97 A device (MEMS10)                                      
  PO9393 23-Sep-97 A Device and Method (MEMS11)                           
  PP0875 12-Dec-97 A Device (MEMS12)                                      
  PP0894 12-Dec-97 A Device and Method (MEMS13)                           
______________________________________                                    
 
    
     IR Technologies 
     Further, the present application may include the utilization of a disposable camera system such as those described in the following Australian provisional patent specifications incorporated here by cross-reference: 
     
         ______________________________________                                    
Australian                                                                
  Provisional                                                             
  Number Filing Date Title                                                
______________________________________                                    
PO0895    12-Dec-97  An Image Creation Method and                         
    Apparatus (IR01)                                                      
  PP0870 12-Dec-97 A Device and Method (IR02)                             
  PP0869 12-Dec-97 A Device and Method (IR04)                             
  PP0887 12-Dec-97 Image Creation Method and                              
    Apparatus (IR05)                                                      
  PP0885 12-Dec-97 An Image Production System (IR06)                      
  PP0884 12-Dec-97 Image Creation Method and                              
    Apparatus (IR10)                                                      
  PP0886 12-Dec-97 Image Creation Method and                              
    Apparatus (IR12)                                                      
  PP0871 12-Dec-97 A Device and Method (IR13)                             
  PP0876 12-Dec-97 An Image Processing Method and                         
    Apparatus (IR14)                                                      
  PP0877 12-Dec-97 A Device and Method (IR16)                             
  PP0878 12-Dec-97 A Device and Method (IR17)                             
  PP0879 12-Dec-97 A Device and Method (IR18)                             
  PP0883 12-Dec-97 A Device and Method (IRI9)                             
  PP0880 12-Dec-97 A Device and Method (IR20)                             
  PP0881 12-Dec-97 A Device and Method (IR21)                             
______________________________________                                    
 
    
     DotCard Technologies 
     Further, the present application may include the utilization of a data distribution system such as that described in the following Australian provisional patent specifications incorporated here by cross-reference: 
     
         ______________________________________                                    
Australian                                                                
  Provisional                                                             
  Number Filing Date Title                                                
______________________________________                                    
PP2370    16-Mar-98  Data Processing Method and                           
    Apparatus (Dot01)                                                     
  PP2371 16-Mar-98 Data Processing Method and                             
    Apparatus (Dot02)                                                     
______________________________________                                    
 
    
     Artcam Technologies 
     Further, the present application may include the utilization of camera and data processing techniques such as an Artcam type device as described in the following Australian provisional patent specifications incorporated here by cross-reference: 
     
         ______________________________________                                    
Australian                                                                
  Provisional                                                             
  Number Filing Date Title                                                
______________________________________                                    
PO7991    15-Jul-97  Image Processing Method and                          
    Apparatus (ART01)                                                     
  PO8505 11-Aug-97 Image Processing Method and                            
    Apparatus (ART01a)                                                    
  PO7988 15-Jul-97 Image Processing Method and                            
    Apparatus (ART02)                                                     
  PO7993 15-Jul-97 Image Processing Method and                            
    Apparatus (ART03)                                                     
  PO8012 15-Jul-97 Image Processing Method and                            
    Apparatus (ART05)                                                     
  PO8017 15-Jul-97 Image Processing Method and                            
    Apparatus (ART06)                                                     
  PO8014 15-Jul-97 Media Device (ART07)                                   
  PO8025 15-Jul-97 Image Processing Method and                            
    Apparatus (ART08)                                                     
  PO8032 15-Jul-97 Image Processing Method and                            
    Apparatus (ART09)                                                     
  PO7999 15-Jul-97 Image Processing Method and                            
    Apparatus (ART10)                                                     
  PO7998 15-Jul-97 Image Processing Method and                            
    Apparatus (ART11)                                                     
  PO8031 15-Jul-97 Image Processing Method and                            
    Apparatus (ART12)                                                     
  PO8030 15-Jul-97 Media Device (ART13)                                   
  PO8498 11-Aug-97 Image Processing Method and                            
    Apparatus (ART14)                                                     
  PO7997 15-Jul-97 Media Device (ART15)                                   
  PO7979 15-Jul-97 Media Device (ART16)                                   
  PO8015 15-Jul-97 Media Device (ART17)                                   
  PO7978 15-Jul-97 Media Device (ART18)                                   
  PO7982 15-Jul-97 Data Processing Method and                             
    Apparatus (ART19)                                                     
  PO7989 15-Jul-97 Data Processing Method and                             
    Apparatus (ART20)                                                     
  PO8019 15-Jul-97 Media Processing Method and                            
    Apparatus (ART21)                                                     
  PO7980 15-Jul-97 Image Processing Method and                            
    Apparatus (ART22)                                                     
  PO7942 15-Jul-97 Image Processing Method and                            
    Apparatus (ART23)                                                     
  PO8018 15-Jul-97 Image Processing Method and                            
    Apparatus (ART24)                                                     
  PO7938 15-Jul-97 Image Processing Method and                            
    Apparatus (ART25)                                                     
  PO8016 15-Jul-97 Image Processing Method and                            
    Apparatus (ART26)                                                     
  PO8024 15-Jul-97 Image Processing Method and                            
    Apparatus (ART27)                                                     
  PO7940 15-Jul-97 Data Processing Method and                             
    Apparatus (ART28)                                                     
  PO7939 15-Jul-97 Data Processing Method and                             
    Apparatus (ART29)                                                     
  PO8501 11-Aug-97 Image Processing Method and                            
    Apparatus (ART30)                                                     
  PO8500 11-Aug-97 Image Processing Method and                            
    Apparatus (ART31)                                                     
  PO7987 15-Jul-97 Data Processing Method and                             
    Apparatus (ART32)                                                     
  PO8022 15-Jul-97 Image Processing Method and                            
    Apparatus (ART33)                                                     
  PO8497 11-Aug-97 Image Processing Method and                            
    Apparatus (ART30)                                                     
  PO8029 15-Jul-97 Sensor Creation Method and                             
    Apparatus (ART36)                                                     
  PO7985 15-Jul-97 Data Processing Method and                             
    Apparatus (ART37)                                                     
  PO8020 15-Jul-97 Data Processing Method and                             
    Apparatus (ART38)                                                     
  PO8023 15-Jul-97 Data Processing Method and                             
    Apparatus (ART39)                                                     
  PO9395 23-Sep-97 Data Processing Method and                             
    Apparatus (ART4)                                                      
  PO8021 15-Jul-97 Data Processing Method and                             
    Apparatus (ART40)                                                     
  PO8504 11-Aug-97 Image Processing Method and                            
    Apparatus (ART42)                                                     
  PO8000 15-Jul-97 Data Processing Method and                             
    Apparatus (ART43)                                                     
  PO7977 15-Jul-97 Data Processing Method and                             
    Apparatus (ART44)                                                     
  PO7934 15-Jul-97 Data Processing Method and                             
    Apparatus (ART45)                                                     
  PO7990 15-Jul-97 Data Processing Method and                             
    Apparatus (ART46)                                                     
  PO8499 11-Aug-97 Image Processing Method and                            
    Apparatus (ART47)                                                     
  PO8502 11-Aug-97 Image Processing Method and                            
    Apparatus (ART48)                                                     
  PO7981 15-Jul-97 Data Processing Method and                             
    Apparatus (ART50)                                                     
  PO7986 15-Jul-97 Data Processing Method and                             
    Apparatus (ART51)                                                     
  PO7983 15-Jul-97 Data Processing Method and                             
    Apparatus (ART52)                                                     
  PO8026 15-Jul-97 Image Processing Method and                            
    Apparatus (ART53)                                                     
  PO8027 15-Jul-97 Image Processing Method and                            
    Apparatus (ART54)                                                     
  PO8028 15-Jul-97 Image Processing Method and                            
    Apparatus (ART56)                                                     
  PO9394 23-Sep-97 Image Processing Method and                            
    Apparatus (ART57)                                                     
  PO9396 23-Sep-97 Data Processing Method and                             
    Apparatus (ART58)                                                     
  PO9397 23-Sep-97 Data Processing Method and                             
    Apparatus (ART59)                                                     
  PO9398 23-Sep-97 Data Processing Method and                             
    Apparatus (ART60)                                                     
  PO9399 23-Sep-97 Data Processing Method and                             
    Apparatus (ART61)                                                     
  PO9400 23-Sep-97 Data Processing Method and                             
    Apparatus (ART62)                                                     
  PO9401 23-Sep-97 Data Processing Method and                             
    Apparatus (ART63)                                                     
  PO9402 23-Sep-97 Data Processing Method and                             
    Apparatus (ART64)                                                     
  PO9403 23-Sep-97 Data Processing Method and                             
    Apparatus (ART65)                                                     
  PO9405 23-Sep-97 Data Processing Method and                             
    Apparatus (ART66)                                                     
  PP0959 16-Dec-97 A Data Processing Method                               
    and Apparatus (ART68)                                                 
  PP1397 19-Jan-98 A Media Device (ART69)                                 
______________________________________