Inkjet printhead with high nozzle area density

• US 7,252,366 B2
• Filed: 04/07/2003
• Issued: 08/07/2007
• Est. Priority Date: 07/15/1997
• Status: Expired due to Fees

• Current Assignee: Memjet Technology Ltd. (Memjet Limited)
• Original Assignee: Silverbrook Research Pty Limited
• Inventors: Silverbrook, Kia
• Primary Examiner(s): Do; An H.
• Application Number:
  US10/407,207
• Publication Number:
  US 20040008237A1
• Time in Patent Office: 1,583 Days
• Field of Search: 347/40, 347/54
• US Class Current: 347/54
• CPC Class Codes: B41J 2/14 Structure thereof only for on-demand ink jet heads
• CPC Class Codes: B41J 2/14314 Structure of ink jet print heads with electrostatically actuated membrane
• CPC Class Codes: B41J 2/14427 Structure of ink jet print heads with thermal bend detached actuators
• CPC Class Codes: B41J 2/16 Production of nozzles
• CPC Class Codes: B41J 2/1623 bonding and adhesion
• CPC Class Codes: B41J 2/1626 etching
• CPC Class Codes: B41J 2/1628 dry etching
• CPC Class Codes: B41J 2/1629 wet etching
• CPC Class Codes: B41J 2/1631 photolithography
• CPC Class Codes: B41J 2/1632 machining
• CPC Class Codes: B41J 2/1635 dividing the wafer into individual chips
• CPC Class Codes: B41J 2/1637 molding
• CPC Class Codes: B41J 2/1639 sacrificial molding
• CPC Class Codes: B41J 2/1642 thin film formation by CVD [chemical vapor deposition]
• CPC Class Codes: B41J 2/1643 thin film formation by plating
• CPC Class Codes: B41J 2/1645 thin film formation by spincoating
• CPC Class Codes: B41J 2/1646 thin film formation by sputtering
• CPC Class Codes: B41J 2/1648 Production of print heads with thermal bend detached actuators
• CPC Class Codes: B41J 2/16585 for paper-width or non-reciprocating print heads
• CPC Class Codes: B41J 2/17513 Inner structure
• CPC Class Codes: B41J 2/17596 : Ink pumps, ink valves
• CPC Class Codes: B41J 2002/041 : Electromagnetic transducer
• CPC Class Codes: B41J 2002/14346 : Ejection by pressure produced by thermal deformation of ink chamber, e.g. buckling
• CPC Class Codes: B41J 2002/14435 : Moving nozzle made of thermal bend detached actuator
• CPC Class Codes: B41J 2002/14443 : Nozzle guard
• CPC Class Codes: B41J 2202/21 : Line printing
• CPC Class Codes: G06F 21/79 : in semiconductor storage media, e.g. directly-addressable memories
• CPC Class Codes: G06F 21/86 : Secure or tamper-resistant housings
• CPC Class Codes: G06F 2221/2129 : Authenticate client device independently of the user
• CPC Class Codes: G06K 1/121 : by printing code marks applying code marks to labels B65C9/46; marking or coding completed packages B65B61/26
• CPC Class Codes: G06K 19/06037 : multi-dimensional coding
• CPC Class Codes: G06K 7/14 : using light without selection of wavelength, e.g. sensing reflected white light G06K7/10831 - G06K7/1097 take precedence
• CPC Class Codes: G06K 7/1417 : 2D bar codes
• CPC Class Codes: G07F 7/08 : by coded identity card or credit card or other personal identification means without personal verification means G07F7/02
• CPC Class Codes: G07F 7/086 : by passive credit-cards adapted therefor, e.g. constructive particularities to avoid counterfeiting, e.g. by inclusion of a physical or chemical security-layer for security documents G07D7/00; for the reading of record-carriers in general G06K7/00; for the design of coded credit-cards G06K19/10
• CPC Class Codes: G07F 7/12 : Card verification
• CPC Class Codes: G11C 11/56 : using storage elements with more than two stable states represented by steps, e.g. of voltage, current, phase, frequency
• CPC Class Codes: H04N 23/00 : Cameras or camera modules comprising electronic image sensors; Control thereof
• CPC Class Codes: H04N 5/2628 : Alteration of picture size, shape, position or orientation, e.g. zooming, rotation, rolling, perspective, translation
• CPC Class Codes: Y10T 29/49083 : Heater type
• CPC Class Codes: Y10T 29/49117 : Conductor or circuit manufacturing
• CPC Class Codes: Y10T 29/49128 : Assembling formed circuit to base
• CPC Class Codes: Y10T 29/49169 : Assembling electrical component directly to terminal or elongated conductor
• CPC Class Codes: Y10T 29/49172 : by molding of insulating material
• CPC Class Codes: Y10T 29/49401 : Fluid pattern dispersing device making, e.g., ink jet

Abstract

Inkjet printheads with high nozzle areal density are disclosed. Various structures are shown where the areal density of nozzles is greater than 200 million per square meter.

Claims

1. An inkjet drop ejection device comprising a plurality of drop ejection apparati on a substrate, each of said drop ejection apparati comprising a chamber, an actuator and a nozzle, wherein drops of ink are ejected through said nozzle, and wherein the plurality of drop ejection apparati comprise a two dimensional array of at least two rows, wherein the spacing between apparati within a row and the spacing between said rows is such that the areal density of the two dimensional array of said drop ejection apparati on said substrate is greater than 50,000,000 per square meter.

2. An inkjet drop ejection device as claimed in claim 1 wherein the spacing between apparati within a row and the spacing between said rows is such that the areal density of said drop ejection apparati on said substrate is greater than 100,000,000 per square meter.

3. An inkjet drop ejection device as claimed in claim 1 wherein the spacing between apparati within a row and the spacing between said rows is such that the areal density of said drop ejection apparati on said substrate is greater than 200,000,000 per square meter.

4. An inkjet drop ejection device as claimed in claim 1 wherein the spacing between apparati within a row and the spacing between said rows is such that the areal density of said drop ejection apparati on said substrate is greater than 390,000,000 per square meter.

5. An inkjet drop ejection device as claimed in claim 1 wherein the spacing between apparati within a row and the spacing between said rows is such that the areal density of said drop ejection apparati on said substrate is greater than 480,000,000 per square meter.

6. An inkjet drop ejection device as claimed in claim 1 wherein said actuator comprises an electrothermal heater which heats ink in said chamber above the boiling point of the ink, causing a bubble to form, said bubble ejecting ink drops from said nozzle.

7. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator comprises an piezoelectric crystal which either expands, shears, or bends to apply pressure to the ink, ejecting drops from said nozzle.

8. An inkjet drop ejection apparatus as claimed in claim 1 wherein an electric field is used to activate electrostriction in relaxor materials from which said actuator is formed.

9. An inkjet drop ejection apparatus as claimed in claim 1 wherein an electric field is used to induce a phase transition between the antiferroelectric and ferroelectric phase of a material forming said actuator.

10. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator comprises conductive plates which are separated by a compressible or fluid dielectric, and wherein a voltage is applied to said plates, causing said plates to attract each other and displace ink, said displacement resulting in ejection of ink drops from said nozzle.

11. An inkjet drop ejection apparatus as claimed in claim 1 wherein a strong electric field is applied to the ink, whereupon electrostatic attraction accelerates the ink towards the print medium.

12. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator comprises an electromagnet which directly attracts a permanent magnet, which causes ejection of, or assists in causing ejection of, ink from said nozzle.

13. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator comprises a solenoid which induces a magnetic field in a soft magnetic core, said magnetic core being in two parts, and said magnetic field causing said two parts of said magnetic core to attract, which causes ejection of, or assists in causing ejection of, ink from said nozzle.

14. An inkjet drop ejection apparatus as claimed in claim 1 wherein Lorenz force acting on said actuator is utilized to eject or assist in ejecting drops of ink from said nozzle.

15. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator utilizes giant magnetostrictive effect of materials to eject or assist in ejecting drops of ink from said nozzle.

16. An inkjet drop ejection apparatus as claimed in claim 1 wherein ink under positive pressure is held in a nozzle by surface tension, and wherein said actuator reduces said surface tension of the ink below the bubble threshold, causing said ink to egress from said nozzle.

17. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator locally reduces said viscosity of the ink in selected nozzles from which ink is to be ejected, and where said reduction of viscosity aids in the ejection of ink from said selected nozzles.

18. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator generates an acoustic wave which is focused upon the region from which a drop is to be ejected.

19. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator utilizes differential thermal expansion upon Joule heating to eject or to aid in ejection of drops from said nozzle.

20. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator comprises a material with a very high coefficient of thermal expansion, and wherein said actuator ejects or assists in ejecting ink from said nozzle.

21. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator comprises a polymer with a high coefficient of thermal expansion which is doped with conducting substances to increase its conductivity, and wherein said doped polymer is resistively heated, and wherein said resistive heating results in mechanical motion which ejects or assists in ejecting ink from said nozzle.

22. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator comprises a shape memory alloy which is thermally switched between its martensitic state and its austenic state, and wherein the resultant shape change of said actuator cause ejection of, or assists in causing ejection of, ink from said nozzle.

23. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator is a linear magnetic actuator which causes ejection of, or assists in causing ejection of, ink from said nozzle.

24. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator supplies sufficient kinetic energy to expel a drop of ink from said nozzle.

25. An inkjet drop ejection device as claimed in claim 1 wherein drops are selected by energizing said actuator and said selected drops are separated from the ink in said nozzle by contact with the print medium or a transfer roller.

26. An inkjet drop ejection apparatus as claimed in claim 1 wherein drops are selected by energizing said actuator and said selected drops are separated from the ink in said nozzle by a strong electric field.

27. An inkjet drop ejection apparatus as claimed in claim 1 wherein drops are selected by energizing said actuator and said selected drops are separated from magnetic ink in said nozzle by a strong magnetic field.

28. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator moves a shutter to block ink flow to said nozzle, and wherein the pressure of the ink pressure is pulsed at a multiple of the drop ejection frequency.

29. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator moves a shutter to block ink flow through a grill to the nozzle.

30. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator controls a catch which prevents an ink pusher from moving when a drop is not to be ejected.

31. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator directly fires the ink drop from said nozzle, without the assistance of an external field.

32. An inkjet drop ejection apparatus as claimed in claim 1 wherein The pressure of the ink oscillates, providing much of the required energy to eject drops from said nozzle, and wherein said actuator selects which drops are to be fired by selectively blocking or enabling nozzles.

33. An inkjet drop ejection apparatus as claimed in claim 1 wherein selected drops protrude from said nozzle further than unselected drops, and contact the print medium, and wherein said selected drops soak into said print medium fast enough to cause separation of said selected drops from the remaining ink in said nozzle.

34. An inkjet drop ejection device as claimed in claim 1 wherein ink drops are printed to a transfer roller.

35. An inkjet drop ejection apparatus as claimed in claim 1 wherein an electric field is used to accelerate selected drops towards the print medium.

36. An inkjet drop ejection apparatus as claimed in claim 1 wherein a magnetic field is used to accelerate selected drops of magnetic ink towards the print medium.

37. An inkjet drop ejection apparatus as claimed in claim 1 wherein said drop ejection apparatus is placed in a constant magnetic field, and Lorenz force in a current carrying wire is used to move said actuator.

38. An inkjet drop ejection apparatus as claimed in claim 1 wherein a pulsed magnetic field is used to cyclically attract a paddle, which pushes on the ink, ejecting drops from said nozzle, and wherein said actuator moves a catch, said catch selectively preventing said paddle from moving.

39. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator directly drives the drop ejection process and no mechanical amplification of the motion of said actuator is used.

40. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator is a differential expansion bend actuator which converts a high force low travel actuator mechanism to high travel, lower force mechanism.

41. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator is a trilayer bend actuator where the two outside layers are substantially identical.

42. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator loads a spring, and wherein when said actuator is turned off, said spring releases.

43. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator comprises a stacked series of thin actuators.

44. An inkjer drop ejection apparatus as claimed in claim 1 wherein said actuator comprises multiple smaller actuators which are used simultaneously to move the ink.

45. An inkjet drop ejection apparatus as claimed in claim 1 wherein a linear spring is used to transform a motion with small travel and high force into a longer travel, lower force motion.

46. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator is a coiled bend actuator.

47. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator is a bend actuator which has a small region near a fixture point, and wherein said small region flexes much more readily than the remainder of said actuator.

48. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator controls a small catch, said catch either enabling or disabling movement of an ink pusher.

49. An inkjet drop ejection apparatus as claimed in claim 1 wherein gears are used to increase travel of said actuator.

50. An inkjet drop ejection apparatus as claimed in claim 1 wherein a buckle plate is used to increase the speed or travel of said actuator.

51. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator comprises a tapered magnetic pole.

52. An inkjet drop ejection apparatus as claimed in claim 1 wherein a lever and fulcrum is used to transform the motion of said actuator.

53. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator is connected to a rotary impeller.

54. An inkjet drop ejection apparatus as claimed in claim 1 wherein an acoustic lens is used to concentrate sound waves generated by said actuator.

55. An inkjet drop ejection apparatus as claimed in claim 1 wherein an electrostatic field is used to cause or assist in drop ejection from said nozzle, and a sharp point is used to concentrate said electrostatic field.

56. An inkjet drop ejection apparatus as claimed in claim 1 wherein the volume of said actuator changes when actuated.

57. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator moves in a direction normal to the surface of a printhead comprising said drop ejection apparatus.

58. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator moves in a direction parallel to the surface of a printhead comprising said drop ejection apparatus.

59. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator is used to push a stiff membrane that is in contact with ink in said chamber.

60. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator causes the rotation of an element of said drop ejection apparatus.

61. An inkjet drop ejection device as claimed in claim 1 wherein said actuator bends when energized.

62. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator swivels around a pivot when energized.

63. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator is normally bent, and straightens when energized.

64. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator bends in one direction when one element is energized, and bends in an opposing direction when another element is energized.

65. An inkjet drop ejection apparatus as claimed in claim 1 wherein energizing said actuator causes a shear motion in material from which said actuator is composed.

66. An inkjet drop ejection device as claimed in claim 1 wherein said actuator squeezes an ink reservoir in said chamber.

67. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator is coiled and either coils further, or uncoils when energized.

68. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator bows or buckles in the middle when energized.

69. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator comprises two shutter controlling actuators, one of which pulls said shutter, and the other pushes said shutter.

70. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator comprises a set of actuators which curl inwards when energized, reducing the volume of ink that said set of actuators enclose.

71. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator comprises a set of actuators which curl outwards when energized, pressurizing ink in said chamber surrounding said set of actuators, and expelling ink from said nozzle.

72. An inkjet drop ejection apparatus as claimed in claim 1 wherein a plurality of vanes enclose a volume of ink, said vanes simultaneously rotating when said actuator is energized, and said vanes being arranged so that the volume of ink between said vanes reduces when said vanes rotate.

73. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator vibrates at a high frequency.

74. An inkjet drop ejection apparatus as claimed in claim 1 wherein said actuator does not physically move at it causes ejection of, or assists in causing ejection of, ink from said nozzle.

75. An inkjet drop ejection device as claimed in claim 1 wherein said chamber is refilled after drop ejection by the surface tension of the ink.

76. An inkjet drop ejection device as claimed in claim 1 wherein ink to said chamber is refilled after drop ejection by a cycle of positive ink pressure, and wherein said chamber is prevented from emptying during a subsequent cycle of negative ink pressure by a shutter which is moved into place by said actuator.

77. An inkjet drop ejection apparatus as claimed in claim 1 wherein ink to said chamber is refilled by a second actuator.

78. An inkjet drop ejection apparatus as claimed in claim 1 wherein ink in said chamber is at a slight positive pressure and said chamber refills by the action of both the surface tension of the ink and the positive ink pressure.

79. An inkjet drop ejection apparatus as claimed in claim 1 wherein ink in said chamber is restricted from flowing out of an ink inlet to said chamber during drop ejection by viscous drag from a relatively long and narrow ink inlet channel.

80. An inkjet drop ejection apparatus as claimed in claim 1 wherein ink in said chamber is restricted from flowing out of an ink inlet to said chamber during drop ejection by positive ink pressure.

81. An inkjet drop ejection apparatus as claimed in claim 1 wherein ink in said chamber is restricted from flowing out of an ink inlet to said chamber during drop ejection by one or more baffles.

82. An inkjet drop ejection apparatus as claimed in claim 1 wherein ink in said chamber is restricted from flowing our of an ink inlet to said chamber during drop ejection by a flexible flap.

83. An inkjet drop ejection apparatus as claimed in claim 1 wherein ink in said chamber is restricted from flowing out of an ink inlet to said chamber during drop ejection by a filter located in said inlet.

84. An inkjet drop ejection apparatus as claimed in claim 1 wherein ink in said chamber is restricted from flowing out of an ink inlet to said chamber during drop ejection by a cross sectional area of said inlet being smaller than the cross sectional area of said nozzle.

85. An inkjet drop ejection apparatus as claimed in claim 1 wherein ink in said chamber is restricted from flowing out of an ink inlet to said chamber during drop ejection by a shutter controlled by a second actuator.

86. An inkjet drop ejection apparatus as claimed in claim 1 wherein ink in said chamber is restricted from flowing out of an ink inlet to said chamber during drop ejection by location of said inlet behind an ink pushing surface.

87. An inkjet drop ejection apparatus as claimed in claim 1 wherein ink in said chamber is restricted from flowing out of an ink inlet to said chamber during drop ejection by part of said actuator, which moves when energized to close off said inlet.

88. An inkjet drop ejection device as claimed in claim 1 wherein said actuator is configured so as to not cause ink flow out of an ink inlet to said chamber during drop ejection.

89. An inkjet drop ejection apparatus as claimed in claim 1 wherein ink is prevented from drying out in said nozzle by ejecting ink front said nozzle periodically, before the ink has time to dry.

90. An inkjet drop ejection apparatus as claimed in claim 1 wherein dried or partially dried ink in said nozzle is cleared by providing more energy to said actuator than is normally used for drop ejection.

91. An inkjet drop ejection apparatus as claimed in claim 1 wherein dried or partially dried ink in said nozzle is cleared by energizing said actuator in rapid succession.

92. An inkjet drop ejection apparatus as claimed in claim 1 wherein dried or partially dried ink in said nozzle is cleared by providing an enhanced drive to said actuator.

93. An inkjet drop ejection apparatus as claimed in claim 1 wherein dried or partially dried ink in said nozzle is cleared by applying an ultrasonic wave to said ink chamber.

94. An inkjet drop ejection apparatus as claimed in claim 1 wherein dried or partially dried ink in said nozzle is cleared by pushing a microfabricated plate against said nozzle, said microfabricated plate comprising a plurality of posts, said post moving through said nozzle opening when said plate is pushed against said nozzle.

95. An inkjet drop ejection apparatus as claimed in claim 1 wherein dried or partially dried ink in said nozzle is cleared by temporarily increasing the pressure of the ink in said chamber until ink streams from said nozzles.

96. An inkjet drop ejection apparatus as claimed in claim 1 wherein dried or partially dried ink in said nozzle is cleared by a flexible blade which is wiped across the surface of said nozzle.

97. An inkjet drop ejection apparatus as claimed in claim 1 wherein dried or partially dried ink in said nozzle is cleared by energizing a heater which is provided at the nozzle;

said heater not being part of the drop ejection process.

98. An inkjet drop ejection apparatus as claimed in claim 1 wherein a plate containing said nozzle is fabricated from electroformed nickel.

99. An inkjet drop ejection apparatus as claimed in claim 1 wherein the hole forming said nozzle is formed by laser ablation.

100. An inkjet drop ejection apparatus as claimed in claim 1 wherein a plate containing said nozzle is microfabricated from silicon.

101. An inkjet drop ejection apparatus as claimed in claim 1 wherein said nozzles are formed from glass capillaries.

102. An inkjet drop ejection apparatus as claimed in claim 1 wherein the surface containing said nozzle plate is deposited as a layer using VLSI deposition techniques, and said nozzle is etched in said nozzle containing surface.

103. An inkjet drop ejection apparatus as claimed in claim 1 wherein the surface containing said nozzle is a layer buried in the substrate upon which said inkjet drop ejection apparatus is formed, and wherein said nozzle is etched in said buried layer.

104. An inkjet drop ejection apparatus as claimed in claim 1 wherein said nozzle is a virtual nozzle formed by acoustic concentration or inertial confinement, and which is formed on demand when an ink drop is to be ejected.

105. An inkjet drop ejection apparatus as claimed in claim 1 wherein said nozzle is formed by the walls of a trough through which a paddle moves.

106. An inkjet drop ejection apparatus as claimed in claim 1 wherein said nozzle is a slit shared by many drop ejection actuators.

107. An inkjet drop ejection device as claimed in claim 1 wherein ink drops are ejected from the edge of the substrate upon which said drop ejection apparatus is formed.

108. An inkjet drop ejection device as claimed in claim 1 wherein ink drops are ejected from the surface of the substrate upon which said drop ejection apparatus is formed, substantially normal to said substrate surface.

109. An inkjet drop ejection device as claimed in claim 1 wherein ink flows through the substrate upon which said drop ejection apparatus is formed, and ink drops are ejected from the front surface of said substrate.

110. An inkjet drop ejection device as claimed in claim 1 wherein ink flows through the substrate upon which said drop ejection apparatus is formed, and ink drops are ejected from the rear surface of said substrate.

111. An inkjet drop ejection device as claimed in claim 1 wherein ink flows through said actuator during the process of drop ejection.

112. An inkjet drop ejection apparatus as claimed in claim 1 wherein said ink comprises water and a colorant, and wherein said colorant comprises a dye.

113. An inkjet drop ejection apparatus as claimed in claim 1 wherein said ink comprises water and a colorant and wherein said colorant comprises a pigment.

114. An inkjet drop ejection apparatus as claimed in claim 1 wherein said ink comprises methyl ethyl ketone.

115. An inkjet drop ejection apparatus as claimed in claim 1 wherein said ink comprises an alcohol.

116. An inkjet drop ejection apparatus as claimed in claim 1 wherein said ink The ink is solid at room temperature, and is melted before jetting from said nozzle.

117. An inkjet drop ejection apparatus as claimed in claim 1 wherein said ink comprises an oil.

118. An inkjet drop ejection apparatus as claimed in claim 1 wherein said ink comprises a microemulsion.

119. An office printer comprising an ink jet drop ejection apparatus as claimed in claim 1.

120. A short run digital printer comprising an inkjet drop ejection apparatus as claimed in claim 1.

121. A high speed digital printer comprising an inkjet drop ejection apparatus as claimed in claim 1.

122. A notebook computer incorporating a printer comprising an inkjet drop ejection apparatus as claimed in claim 1.

123. An offset press supplemental printer comprising an inkjet drop ejection apparatus as claimed in claim 1.

124. A pagewidth printer comprising an inkjet drop ejection apparatus as claimed in claim 1.

125. A portable printer comprising an inkjet drop ejection apparatus as claimed in claim 1.

126. A copier comprising an inkjet drop ejection apparatus as claimed in claim 1.

127. A facsimile machine comprising an inkjet drop ejection apparatus as claimed in claim 1.

128. A label printer comprising an inkjet drop ejection apparatus as claimed in claim 1.

129. A large format printer comprising an inkjet drop ejection apparatus as claimed in claim 1.

130. A photograph copier comprising an inkjet drop ejection apparatus as claimed in claim 1.

131. A digital photographic minilab incorporating a printer comprising an inkjet drop ejection apparatus as claimed in claim 1.

132. A vipeo printer comprising an inkjet drop ejection apparatus as claimed in claim 1.

133. A PDA incorporating a printer comprising an inkjet drop ejection apparatus as claimed in claim 1.

134. A wallpaper printer comprising an inkjet drop ejection apparatus as claimed in claim 1.

135. An indoor sign printer comprising un inkjet drop ejection apparatus as claimed in claim 1.

136. A billboard printer comprising an inkjet drop ejection apparatus as claimed in claim 1.

137. A fabric printer comprising an inkjet drop ejection apparatus as claimed in claim 1.

138. A camera printer comprising an inkjet drop ejection apparatus as claimed in claim 1.

139. A commercial printer array comprising an inkjet drop ejection apparatus as claimed in claim 1.