(12) United States Patent
`Silverbrook
`
`US006416167B1
`(16) Patent N6.=
`US 6,416,167 B1
`(45) Date of Patent:
`Jul. 9, 2002
`
`(54) THERMALLY ACTUATED INK JET
`PRINTING MECHANISM HAVING A SERIES
`0F THERMAL ACTUATOR UNITS
`
`(75) Inventor: Kia Silverbrook, Sydney (AU)
`(73) Assignee: Silverbrook Research Pty Ltd,
`Balmain (AU)
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U30 154(k)) by 0 days_
`
`(>e) Notice:
`
`(21) Appl. No.: 09/112,767
`(22) Filed:
`JuL 10’ 1998
`_
`_
`_
`_
`_
`Forelgn Apphcatlon Pnonty Data
`(30)
`Jul. 15, 1997
`(AU) ............................................ .. PO7991
`Mar. 25, 1998
`(AU) ............................................ .. PP2592
`7
`_
`_
`(51) Int‘ Cl‘ """"""""""""" " B41J 2/015’ Bélglili/i
`_
`_
`_
`(52) US. Cl. ........................... .. 347/54, 347/20, 3344776127,
`_
`(58) Field of Search ............................ .. 347/44,
`
`/6612,
`
`(56)
`
`References Cited
`FOREIGN PATENT DOCUMENTS
`
`Primary Examiner—John Barlow
`Assistant Examiner_An H, Do
`
`(57)
`
`ABSTRACT
`
`An inkj et nozzle arrangement is disclosed including a noZZle
`chamber having an ?uid ejection noZZle in one surface of the
`chamber; a paddle vane located Within the chamber, the
`paddle vane being adapted to be actuated by an actuator
`device for the ejection of ?uid out of the chamber via the
`?uid ejection noZZle; and a thermal actuator device located
`externally of the noZZle chamber and attached to the paddle
`vane the thermal actuator device including a plurality of
`separate spaced apart elongated thermal actuator units.
`Preferably, the thermal actuator units are interconnected at a
`?rst end to a substrate and at a second end to a rigid strut
`member- The rigid Strut member can, in turn, be intercon
`nected to a lever arm having one end attached to the paddle
`vane. The thermal actuator units can operate upon conduc
`tive heating along a conductive trace and the conductive
`heating includes the generation of a substantial portion of
`the heat in the area adjacent the ?rst end‘ The Conductive
`heating trace can include a thinned cross-section adjacent
`the ?rst end‘ The heating layers of the thermal actuator units
`can include substantially either a copper nickel alloy or
`titanium nitride. The paddle can be constructed from a
`similar conductive material to portions of the thermal actua
`tor units hoWever it is conductively insulated therefrom.
`
`JP
`404001051 A * 1/1992
`* cited by examiner
`
`................ .. 347/54
`
`12 Claims, 7 Drawing Sheets
`
`HP 1012
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`US 6,416,167 B1
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`FIG. 2
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`
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`
`FIG. 5
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`US 6,416,167 B1
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`Jul. 9, 2002
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`Jul. 9, 2002
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`Sheet 4 0f 7
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`US 6,416,167 B1
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`Silicon
`
`Sacri?cial material
`
`f ; Eiaetomer
`
`Boron doped eiiioon
`
`Cupronickei
`
`i’olyimide
`
`?iiicon nitride (6i5N4) QQ CoNiFe or NiFe
`
`L
`
`' indium tin oxide (ITO)
`
`>\\‘ Aluminum
`
`\
`
`Z; Giaee SiO
`2
`
`y
`
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`
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`
`Gold
`
`Permanent magnet % F’TFE
`
`i’olyeilicon
`
`Conductive PTFE
`
`:2
`
`Titanium Nitride iiN
`
`TerFenol-D
`
`Titanium boride (TiBZ)
`
`Shape memory alloy
`
`\\\\\
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`
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`
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`
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`
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`
`Q Tantalum
`
`6
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`54 55
`
`/ /////V/////I /
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`I
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`6
`
`FIG. 70
`
`56
`54 55
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`///////// ///
`
`FIG. 77
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`Jul. 9, 2002
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`Sheet 6 6f 7
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`US 6,416,167 B1
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`55 55 54 55
`57
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`
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`U.S. Patent
`
`Jul. 9, 2002
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`Sheet 7 of 7
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`US 6,416,167 B1
`
`I IIlII|IIIIIIl\|IIII\Illlllllllllmullll|II|I\IHIIIIIIIIIIVIIIIIII1IIIIIIIVIIIHIIVlllmIIIII|1|IIIII4IIIIIHIIIIIIHIIIIHIIIIIIIIIIIIl\lIIIIIlllllllmlllI\II|IIIIIIIIII\II|IIHIIIIIIHIIIIII
`-(gar:/I [III]! I I [III]!!!
`
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`
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`
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`
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`
`7
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`HP 1012
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`

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`US 6,416,167 B1
`
`1
`THERMALLY ACTUATED INK JET
`PRINTING MECHANISM HAVING A SERIES
`0F THERMAL ACTUATOR UNITS
`
`CROSS REFERENCES TO RELATED
`APPLICATIONS
`
`5
`
`The following Australian provisional patent applications
`~
`are hereby Incorporated by cross-reference. For the purposes
`of location and identi?cation, US patent applications iden- 10
`ti?ed by their US patent application serial numbers (USSN)
`are listed alongside the Australian applications from Which
`the US patent applications claim the right of priority
`'
`
`CROSS-REFERENCED
`AUSTRALIAN
`PROVISIONAL
`PATENT
`APPLICATION NO.
`
`US PATENT/PATENT
`APPLICATION (CLAIMING
`RIGHT OF PRIORITY
`FROM AUSTRALIAN PRO-
`VISIONAL APPLICATION) DOCKET NO. 20
`
`15
`
`PO7991
`PO8505
`PO7988
`PO9395
`PO8017
`PO8014
`PO8025
`PO8032
`PO7999
`PO7998
`PO8031
`PO8030
`PO7997
`PO7979
`PO8015
`PC7978
`PO7982
`PO7989
`PO8019
`PO7980
`PO8018
`PO7938
`PO8016
`PO8024
`PO7940
`PO7939
`PO8501
`PO8500
`PO7987
`PO8022
`PO8497
`PO8020
`PO8023
`PO8504
`PO8000
`PO7977
`PO7934
`PO7990
`PO8499
`PO8502
`PO7981
`PO7986
`PO7983
`PO8026
`PO8027
`PO8028
`PO9394
`PO9396
`PO9397
`PO9398
`PO9399
`PO9400
`PO9401
`PO9402
`PO9403
`PO9405
`PPO959
`
`09/113,060
`09/113,070
`09/113,073
`09/112,748
`09/112,747
`09/112,776
`09/112,750
`09/112,746
`09/112,743
`09/112,742
`09/112,741
`09/112,740
`09/112,739
`09/113,053
`09/112,738
`(19/113,067
`09/113,063
`09/113,069
`09/112,744
`09/113,058
`09/112,777
`09/113,224
`09/112,804
`09/112,805
`09/113,072
`09/112,785
`09/112,797
`09/112,796
`09/113,071
`09/112,824
`09/113,090
`09/112,823
`09/113,222
`09/112,786
`09/113,051
`09/112,782
`09/113,056
`09/113,059
`09/113,091
`09/112,753
`09/113,055
`09/113,057
`09/113,054
`09/112,752
`09/112,759
`09/112,757
`09/112,758
`09/113,107
`09/112,829
`09/112,792
`6,106,147
`09/112,790
`09/112,789
`09/112,788
`09/112,795
`09/112,749
`O9/112,784
`
`ART01
`ART02
`ART03
`ART04
`ART06
`ART07
`ART08
`ART09
`ART10
`ART11
`ART12
`ART13
`ART15
`ART16
`ART17
`ART18
`ART19
`ART20
`ART21
`ART22
`ART24
`ART25
`ART26
`ART27
`ART28
`ART29
`ART30
`ART31
`ART32
`ART33
`ART34
`ART38
`ART39
`ART42
`ART43
`ART44
`ART45
`ART46
`ART47
`ART48
`ART50
`ART51
`ART52
`ART53
`ART54
`ART56
`ART57
`ART58
`ART59
`ART60
`ART61
`ART62
`ART63
`ART64
`ART65
`ART66
`ART68
`
`25
`
`30
`
`35
`
`4O
`
`45
`
`50
`
`55
`
`6O
`
`65
`
`2
`
`-continued
`
`CROSS-REFERENCED
`AUSTRALIAN
`PROVISIONAL
`PATENT
`APPLICATION NO.
`
`US PATENT/PATENT
`APPLICATION (CLAIMING
`RIGHT OF PRIORITY
`FROM AUSTRALIAN PRO
`VISIONAL APPLICATION) DOCKET NO.
`
`PP1397
`PP2370
`PP2371
`PO8003
`PO8OO5
`PO94O4
`PO8066
`PO8072
`PO8040
`PO8071
`PO8047
`PO8035
`PO8044
`PO8063
`PO8057
`PO8056
`PO8069
`PO8049
`PO8036
`PO8048
`PO8070
`PO8067
`PO8001
`PO8038
`PO8033
`PO8002
`PO8068
`PO8062
`PO8034
`PO8039
`PO8041
`P080114
`PO8037
`PO8043
`PO8042
`PO8064
`PO9389
`PO9391
`PP0888
`PP0891
`PP0890
`PP0873
`PP0993
`PP0890
`PP1398
`PP2592
`PP2593
`PP3991
`PP3987
`PP3985
`PP3983
`PO7935
`PO7936
`PO7937
`PO8061
`PO8054
`PO8065
`PO8055
`PO8053
`PO8078
`PO7933
`PO7950
`PO7949
`PO8060
`PO8059
`PO8073
`PO8076
`PO8075
`PO8079
`PO8050
`PO8052
`PO7948
`PO7951
`
`09/112,783
`O9/112 781
`O9/113ZO52
`09/112,834
`(19/113403
`O9/113’1O1
`09/112,751
`09/112,787
`09/112,802
`09/112,803
`09/113,097
`09/113,099
`09/113,084
`09/113,066
`09/112,778
`09/112,779
`09/113,077
`09/113,061
`09/112,818
`09/112,816
`09/112,772
`09/112,819
`09/112,815
`09/113,096
`09/113,068
`09/113,095
`09/112,808
`09/112,809
`09/112,780
`09/113,083
`09/113,121
`(19/113,122
`09/112,793
`09/112,794
`09/113,128
`09/113,127
`09/112,756
`09/112,755
`09/112,754
`09/112,811
`09/112,812
`09/112,813
`09/112,814
`09/112,764
`09/112,765
`09/112,767
`09/112,768
`09/112,807
`09/112,806
`09/112,820
`09/112,821
`09/112,822
`09/112,825
`09/112,826
`09/112,827
`09/112,828
`6,071,750
`09/113,108
`09/113,109
`09/113,123
`09/113,114
`09/113,115
`09/113,129
`09/113,124
`09/113,125
`09/113,126
`09/113,119
`09/113,120
`09/113,221
`09/113,116
`09/113,118
`09/113,117
`O9/113,113
`
`ART69
`DOTO1
`DOTOZ
`Fluid01
`F1u}dO2
`Fluldm
`I101
`I102
`I103
`I104
`I105
`I106
`I107
`I108
`I109
`I110
`I111
`I112
`I113
`I114
`I115
`I116
`I117
`I118
`I119
`I120
`I121
`I122
`I123
`I124
`I125
`I126
`I127
`I128
`I129
`I130
`I131
`I132
`I133
`I134
`I135
`I136
`I137
`I138
`I139
`I140
`I141
`I142
`I143
`I144
`I145
`I1M01
`I1M02
`I1M03
`I1M04
`I1M05
`I1M06
`I1M07
`I1M08
`I1M09
`I1M10
`I1M11
`I1M12
`I1M13
`I1M14
`I1M15
`I1M16
`I1M17
`I1M18
`I1M19
`I1M20
`I1M21
`IJM22
`
`HP 1012
`Page 9 of 31
`
`

`
`US 6,416,167 B1
`
`3
`
`-continued
`
`CROSS-REFERENCED
`AUSTRALIAN
`PROVISIONAL
`PATENT
`APPLICATION NO.
`
`US PATENT/PATENT
`APPLICATION (CLAIMING
`RIGHT OF PRIORITY
`FROM AUSTRALIAN PRO
`VISIONAL APPLICATION) DOCKET NO.
`
`PO8074
`PO7941
`PO8077
`PO8058
`PO8051
`PO8045
`PO7952
`PO8046
`PO9390
`PO9392
`PP0889
`PP0887
`PP0882
`PP0874
`PP1396
`PP3989
`PP2591
`PP3990
`PP3986
`PP3984
`PP3982
`PP0895
`PP0870
`PP0869
`PP0887
`PP0885
`PP0884
`PP0886
`PP0871
`PP0876
`PP0877
`PP0878
`PP0879
`PP0883
`PP0880
`PP0881
`PO8006
`PO8007
`PO8008
`PO8010
`PO8011
`PO7947
`PO7944
`PO7946
`PO9393
`PP0875
`PP0894
`
`09/113,130
`09/113,110
`09/113,112
`09/113,087
`09/113,074
`6,111,754
`09/113,088
`09/112,771
`09/112,769
`09/112,770
`09/112,798
`09/112,801
`09/112,800
`09/112,799
`09/113,098
`09/112,833
`09/112,832
`09/112,831
`09/112,830
`09/112,836
`09/112,835
`09/113,102
`09/113,106
`09/113,105
`09/113,104
`09/112,810
`09/112,766
`09/113,085
`09/113,086
`09/113,094
`09/112,760
`09/112,773
`09/112,774
`09/112,775
`09/112,745
`09/113,092
`6,087,638
`09/113,093
`09/113,062
`6,041,600
`09/113,082
`6,067,797
`09/113,080
`6,044,646
`09/113,065
`09/113,078
`09/113,075
`
`IJM23
`IJM24
`IJM25
`IJM26
`IJM27
`IJM28
`IJM29
`IJM30
`IJM31
`IJM32
`IJM35
`IJM36
`IJM37
`IJM38
`IJM39
`IJM40
`IJM41
`IJM42
`IJM43
`IJM44
`IJM45
`IR01
`IR02
`IR04
`IR05
`IR06
`IR10
`IR12
`IR13
`IR14
`IR16
`IR17
`IR18
`IR19
`IR20
`IR21
`MEMS02
`MEMS03
`MEMS04
`MEMS05
`MEMS06
`MEMS07
`MEMS09
`MEMS10
`MEMS11
`MEMS12
`MEMS13
`
`FIELD OF THE INVENTION
`The present invention relates to the ?eld of inkjet printers
`and, discloses an inkjet printing system Which includes a
`bend actuator interconnected into a paddle for the ejection of
`ink through an ink ejection port. The present invention
`further discloses a thermally actuated ink jet printer having
`a series of thermal actuator units.
`
`BACKGROUND OF THE INVENTION
`Many different types of printing have been invented, a
`large number of Which are presently in use. The knoWn
`forms of print have a variety of methods for marking the
`print media With a relevant marking media. Commonly used
`forms of printing include offset printing, laser printing and
`copying devices, dot matrix type impact printers, thermal
`paper printers, ?lm recorders, thermal Wax printers, dye
`sublimation printers and ink jet printers both of the drop on
`demand and continuous ?oW type. Each type of printer has
`its oWn advantages and problems When considering cost,
`speed, quality, reliability, simplicity of construction and
`operation etc.
`
`4
`In recent years, the ?eld of ink jet printing, Wherein each
`individual pixel of ink is derived from one or more ink
`noZZles has become increasingly popular primarily due to its
`inexpensive and versatile nature.
`Many different techniques on ink jet printing have been
`invented. For a survey of the ?eld, reference is made to an
`article by J Moore, “Non-Impact Printing: Introduction and
`Historical Perspective”, Output Hard Copy Devices, Editors
`R Dubeck and S Sherr, pages 207—220 (1988).
`Ink Jet printers themselves come in many different types.
`The utiliZation of a continuous stream of ink in ink jet
`printing appears to date back to at least 1929 Wherein US.
`Pat. No. 1,941,001 by Hansell discloses a simple form of
`continuous stream electro-static ink jet printing.
`US. Pat. No. 3,596,275 by SWeet also discloses a process
`of a continuous ink jet printing including the step Wherein
`the ink jet stream is modulated by a high frequency elec
`trostatic ?eld so as to cause drop separation. This technique
`is still utiliZed by several manufacturers including Elmjet
`and Scitex (see also US. Pat. No. 3,373,437 by SWeet et al)
`Piezoelectric ink jet printers are also one form of com
`monly utiliZed ink jet printing device. PieZoelectric systems
`are disclosed by Kyser et. al. in US. Pat. No. 3,946,398
`(1970) Which utiliZes a diaphragm mode of operation, by
`Zolten in US. Pat. No. 3,683,212 (1970) Which discloses a
`squeeZe mode of operation of a pieZoelectric crystal,
`Stemme in US. Pat. No. 3,747,120 (1972) discloses a bend
`mode of pieZoelectric operation, HoWkins in US. Pat. No.
`4,459,601 discloses a pieZoelectric push mode actuation of
`the ink jet stream and Fischbeck in US. Pat. No. 4,584,590
`Which discloses a shear mode type of pieZoelectric trans
`ducer element.
`Recently, thermal ink jet printing has become an
`extremely popular form of ink jet printing. The ink jet
`printing techniques include those disclosed by Endo et al in
`GB 2007162 (1979) and Vaught et al in US. Pat. No.
`4,490,728. Both the aforementioned references disclosed ink
`jet printing techniques that rely upon the activation of an
`electrothermal actuator Which results in the creation of a
`bubble in a constricted space, such as a noZZle, Which
`thereby causes the ejection of ink from an aperture con
`nected to the con?ned space onto a relevant print media.
`Printing devices utiliZing the electro-thermal actuator are
`manufactured by manufacturers such as Canon and HeWlett
`Packard.
`As can be seen from the foregoing, many different types
`of printing technologies are available. Ideally, a printing
`technology should have a number of desirable attributes.
`These include inexpensive construction and operation, high
`speed operation, safe and continuous long term operation
`etc. Each technology may have its oWn advantages and
`disadvantages in the areas of cost, speed, quality, reliability,
`poWer usage, simplicity of construction operation, durability
`and consumables.
`In the construction of any inkjet printing system, there are
`a considerable number of important factors Which must be
`traded off against one another especially as large scale
`printheads are constructed, especially those of a pageWidth
`type. Anumber of these factors are outlined in the folloWing
`paragraphs.
`Firstly, inkjet printheads are normally constructed utiliZ
`ing micro-electromechanical systems (MEMS) techniques.
`As such, they tend to rely upon standard integrated circuit
`construction/fabrication techniques of depositing planar lay
`ers on a silicon Wafer and etching certain portions of the
`planar layers. Within silicon circuit fabrication technology,
`
`10
`
`15
`
`20
`
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`certain techniques are more Well known than others. For
`example, the techniques associated With the creation of
`CMOS circuits are likely to be more readily used than those
`associated With the creation of exotic circuits including
`ferroelectrics, galium arsenide etc. Hence, it is desirable, in
`any MEMS constructions, to utiliZe Well proven semi
`conductor fabrication techniques Which do not require any
`“exotic” processes or materials. Of course, a certain degree
`of trade off Will be undertaken in that if the advantages of
`using the exotic material far out Weighs its disadvantages
`then it may become desirable to utiliZe the material anyWay.
`With a large ray of ink ejection noZZles, it is desirable to
`provide for a highly automated form of manufacturing
`Which results in an inexpensive production of multiple
`printhead devices.
`Preferably, the device constructed utiliZes a loW amount
`of energy in the ejection of ink. The utiliZation of a loW
`amount of energy is particularly important When a large
`pageWidth full color printhead is constructed having a large
`array of individual print ejection mechanism With each
`ejection mechanisms, in the Worst case, being ?red in a rapid
`sequence.
`
`SUMMARY OF THE INVENTION
`
`It is an object of the present invention to provide an ink
`ejection noZZle arrangement suitable for incorporation into
`an inkjet printhead arrangement for the ejection of ink on
`demand from a noZZle chamber in an ef?cient manner.
`In accordance With a ?rst aspect of the present invention,
`there is provided an inkjet noZZle arrangement comprising a
`noZZle chamber having an ?uid ejection port in one surface
`of the chamber; a paddle vane located Within the chamber,
`the paddle vane being adapted to be actuated by an actuator
`for the ejection of ?uid out of the chamber via the ?uid
`ejection port; and a thermal device located externally of the
`noZZle chamber and attached to the paddle vane, via an arm,
`the thermal actuator device including a plurality of separate
`spaced apart elongate thermal actuator units.
`Preferably, the thermal actuator units are interconnected
`at a ?rst end to a substrate and at a second end to a rigid strut
`member. The rigid strut member can, in turn, be intercon
`nected to the arm having one end attached to the paddle
`vane. The thermal actuator units can operate upon conduc
`tive heating along a conductive trace and the conductive
`heating can include the generation of a substantial portion of
`the heat in the area adjacent the ?rst end. The conductive
`heating trace can include a thinned cross-section adjacent
`the ?rst end. The heating layers of the thermal actuator units
`can comprise substantially either a copper nickel alloy or
`titanium nitride. The paddle can be constructed from a
`similar conductive material to portions of the thermal actua
`tor units hoWever it is conductively insulated therefrom.
`Preferably, the thermal actuator units are constructed from
`multiple layers utiliZing a single mask to etch the multiple
`layers.
`The noZZle chamber can include an actuator access port in
`a second surface of the chamber. The access port can
`comprise a slot in a corner of the chamber and the actuator
`is able to move in an arc through the slot. The actuator can
`include an end portion Which mates substantially With a Wall
`of the chamber at substantially right angles to the paddle
`vane. The paddle vane can include a depressed portion
`substantially opposite the ?uid ejection port.
`In accordance With a further aspect of the present
`invention, there is provided a thermal actuator including a
`series of lever arms attached at one end to a substrate, the
`
`6
`thermal actuator being operational as a result of conductive
`heating of a conductive trace, the conductive trace including
`a thinned cross-section substantially adjacent the attachment
`to the substrate.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`NotWithstanding any other forms Which may fall Within
`the scope of the present invention, preferred forms of the
`invention Will noW be described, by Way of example only,
`With reference to the accompanying draWings in Which:
`FIGS. 1—3 illustrate the basic operational principles of the
`preferred embodiment;
`FIG. 4 illustrates a three dimensional vieW of a single ink
`jet noZZle arrangement constructed in accordance With the
`preferred embodiment;
`FIG. 5 illustrates an array of the noZZle arrangements of
`FIG. 4;
`FIG. 6 shoWs a table to be used With reference to FIGS.
`7 to 16; and
`FIGS. 7 to 16 shoW various stages in the manufacture of
`the ink jet noZZle arrangement of FIG. 4.
`
`DESCRIPTION OF PREFERRED AND OTHER
`EMBODIMENTS
`In the preferred embodiment, there is provided a noZZle
`arrangement having a noZZle chamber containing ink and a
`thermal actuator connected to a paddle positioned Within the
`chamber. The thermal actuator device is actuated so as to
`eject ink from the noZZle chamber. The preferred embodi
`ment includes a particular thermal actuator Which includes a
`series of tapered portions for providing conductive heating
`of a conductive trace. The actuator is connected to the paddle
`via an arm received through a slotted Wall of the noZZle
`chamber. The actuator arm has a mating shape so as to mate
`substantially With the surfaces of the slot in the noZZle
`chamber Wall.
`Turning initially to FIGS. 1—3, there is provided sche
`matic illustrations of the basic operation of a noZZle arrange
`ment of the invention. A noZZle chamber 1 is provided ?lled
`With ink 2 by means of an ink inlet channel 3 Which can be
`etched through a Wafer substrate on Which the noZZle
`chamber rests. The noZZle chamber further includes an ink
`ejection port around Which an ink meniscus forms.
`Inside the noZZle chamber is a paddle type device Which
`is interconnected to an actuator 8 through a slot in the Wall
`of the noZZle chamber. The actuator includes a heater means
`eg. 9 located adjacent to an end portion of a post 10. The post
`10 is ?xed to a substrate.
`When it is desired to eject a drop from the noZZle chamber
`1, as illustrated in FIG. 2, the heater means 9 is heated so as
`to undergo thermal expansion. Preferably, the heater means
`9 itself or the other portions of the actuator 8 are built from
`materials having a high bend ef?ciency Where the bend
`ef?ciency is de?ned as
`
`Young's Modulus>< (Coefficient of thermal Expansion)
`=
`b d f?‘
`Densityxspeci?c Heat Capacity
`en 6 clency
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`A suitable material for the heater elements is a copper
`nickel alloy Which can be formed so as to bend a glass
`material.
`The heater means 9 is ideally located adjacent the end
`portion of the post 10 such that the effects of activation are
`magni?ed at the paddle end 7 such that small thermal
`expansions near the post 10 result in large movements of the
`paddle end.
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`7
`The heater means 9 and consequential paddle movement
`causes a general increase in pressure around the ink menis
`cus 5 Which expands, as illustrated in FIG. 2, in a rapid
`manner. The heater current is pulsed and ink is ejected out
`of the port in addition to ?owing in from the ink channel 3.
`Subsequently, the paddle 7 is deactivated to again return
`to its quiescent position. The deactivation causes a general
`re?oW of the ink into the noZZle chamber. The forWard
`momentum of the ink outside the noZZle rim and the
`corresponding back?oW results in a general necking and
`breaking off of the drop 12 Which proceeds to the print
`media. The collapsed meniscus 5 results in a general sucking
`of ink into the noZZle chamber 2 via the ink ?oW channel 3.
`In time, the noZZle chamber 1 is re?lled such that the
`position in FIG. 1 is again reached and the noZZle chamber
`is subsequently ready for the ejection of another drop of ink.
`FIG. 4 illustrates a side perspective vieW of the noZZle
`arrangement FIG. 5 illustrates sectional vieW through an
`array of noZZle arrangement of FIG. 4. In these ?gures, the
`numbering of elements previously introduced has been
`retained.
`Firstly, the actuator 8 includes a series of tapered actuator
`units eg. 15 Which comprise an upper glass portion
`(amorphous silicon dioxide) 16 formed on top of a titanium
`nitride layer 17. Alternatively a copper nickel alloy layer
`(hereinafter called cupronickel) can be utiliZed Which Will
`have a higher bend ef?ciency Where bend ef?ciency is
`de?ned as:
`
`Young's Modulus>< (Coefficient of thermal Expansion)
`b d f‘ :
`Density>< Speci?c Heat Capacity
`en 6 Emmy
`
`The titanium nitride layer 17 is in a tapered form and, as
`such, resistive heating takes place near an end portion of the
`post 10. Adjacent titanium nitride/glass portions 15 are
`interconnected at a block portion 19 Which also provides a
`mechanical structural support for the actuator 8.
`The heater means 9 ideally includes a plurality of the
`tapered actuator unit 15 Which are elongate and spaced apart
`such that, upon heating, the bending force exhibited along
`the axis of the actuator 8 is maximiZed. Slots are de?ned
`betWeen adjacent tapered units 15 and alloW for slight
`differential operation of each actuator 8 With respect to
`adjacent actuators 8.
`The block portion 19 is interconnected to an arm 20. The
`arm 20 is in turn connected to the paddle 7 inside the noZZle
`chamber 1 by means of a slot eg. 22 formed in the side of
`the noZZle chamber 1. The slot 22 is designed generally to
`mate With the surfaces of the arm 20 so as to minimise
`opportunities for the out?oW of ink around the arm 20. The
`ink is held generally Within the noZZle chamber 1 via surface
`tension effects around the slot 22.
`When it is desired to actuate the arm 20, a conductive
`current is passed through the titanium nitride layer 17 via
`vias Within the block portion 19 connecting to a loWer
`CMOS layer 6 Which provides the necessary poWer and
`control circuitry for the noZZle arrangement. The conductive
`current results in heating of the nitride layer 17 adjacent to
`the post 10 Which results in a general upWard bending of the
`arm 20 and consequential ejection of ink out of the noZZle
`4. The ejected drop is printed on a page in the usual manner
`for an inkjet printer as previously described.
`An array of noZZle arrangements can be formed so as to
`create a single printhead. For example, in FIG. 5 there is
`illustrated a partly sectioned various array vieW Which
`
`8
`comprises multiple ink ejection noZZle arrangements of FIG.
`4 laid out in interleaved lines so as to form a printhead array.
`Of course, different types of arrays can be formulated
`including full color arrays etc.
`The construction of the printhead system described can
`proceed utiliZing standard MEMS techniques through suit
`able modi?cation of the steps as set out in the Australian
`Provisional Patent Speci?cation entitled “Image Creation
`Method and Apparatus (I1 41)” ?led by the present applicant
`simultaneously hereWith the contents of Which are fully
`incorporated by cross reference.
`Fabrication of the ink jet noZZle arrangement is indicated
`in FIGS. 7 to 16. The preferred embodiment achieves a
`particular balance betWeen utiliZation of the standard semi
`conductor processing material such as titanium nitride and
`glass in a MEMS process. Obviously the skilled person may
`make other choices of materials and design features Where
`the economics are justi?ed. For example, a copper nickel
`alloy of 50% copper and 50% nickel may be more advan
`tageously deployed as the conductive heating compound as
`it is likely to have higher levels of bend ef?ciency. Also,
`other design structures may be employed Where it is not
`necessary to provide for such a simple form of manufacture.
`The presently disclosed ink jet printing technology is
`potentially suited to a Wide range of printing system includ
`ing: colour and monochrome of?ce printers, short run digital
`printers, high speed digital printers, offset press supplemen
`tal printers, loW cost scanning printers high speed pageWidth
`printers, notebook computers With inbuilt pageWidth
`printers, portable colour and monochrome printers, colour
`and monochrome copiers, colour and monochrome facsimile
`machines, combined printer, facsimile and copying
`machines, label printers, large format plotters, photograph
`copiers, printers for digital photographic “minilabs”, video
`printers, PHOTO CD (PHOTO CD is a registered trade mark
`of the Eastman Kodak Company) printers, portable printers
`for PDAs, Wallpaper printers, indoor sign printers, billboard
`printers, fabric printers, camera printers and fault tolerant
`commercial printer arrays.
`It Would be appreciated by a person skilled in the art that
`numerous variations and/or modi?cations may be made to
`the present invention as shoWn in the speci?c embodiments
`Without departing from the spirit or scope of the invention as
`broadly described. The present embodiments are, 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 signi?cant problem With thermal ink jet is
`poWer consumption. This is approximately 100 times that
`required for high speed, and stems from the energy
`inef?cient means of drop ejection. This involves the rapid
`boiling of Water to produce a vapor bubble Which expels the
`ink. Water has a very high heat capacity, and must be
`superheated in thermal ink jet applications. This leads to an
`ef?ciency of around 0.02%, from electricity input to drop
`momentum (and increased surface area) out.
`The most signi?cant problem With pieZoelectric ink jet is
`siZe and cost. PieZoelectric crystals have a very small
`de?ection 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 signi?cant problem at the current limit of
`around 300 noZZles per printhead, but is a major impediment
`to the fabrication of pageWidth printheads With 19,200
`noZZles.
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`Ideally, the ink jet technologies used meet the stringent
`requirements of in-camera digital color printing and other
`high quality, high speed, loW cost printing applications. To
`meet the requirements of digital photography, neW ink jet
`technologies have been created. The target features include:
`loW poWer (less than 10 Watts)
`high resolution capability (1,600 dpi or more)
`photographic quality output
`loW manufacturing cost
`small siZe (pageWidth times minimum cross section)
`high speed (<2 seconds per page).
`All of these features can be met or exceeded by the ink jet
`systems described beloW With differing levels of dif?culty.
`Forty-?ve different ink jet technologies have been developed
`by the Assignee to give a Wide range of choices for high
`volume manufacture. These technologies form part of sepa
`rate applications assigned to the present Assignee as set out
`in the table under the heading Cross References to Related
`Applications.
`The ink jet designs shoWn here are suitable for a Wide
`range of digital printing systems, from battery poWered
`one-time use digital cameras, through to desktop and net
`Work printers, and through to commercial printing systems.
`For ease of manufacture using standard process
`equipment, the printhead is designed to be a monolithic 0.5
`micron CMOS chip With MEMS post processing. For color
`photographic applications, the printhead is 100 mm long,
`With a Width Which depends upon the ink jet type. The
`smallest printhead designed is I] 38, Which is 0.35 mm Wide,
`giving a chip area of 35 square mm. The printheads each
`contain 19,200 noZZles plus data and control circuitry.
`Ink is supplied to the back of the printhead by injection
`molded plastic ink channels. The molding requires 50
`micron features, Which can be created using a lithographi
`cally micromachined insert in a standard injection molding
`tool. Ink ?oWs through holes etched through the Wafer to the
`noZZle chambers fabricated on the front surface of the Wafer.
`The printhead is connected to the camera circuitry by tape
`automated bonding.
`Tables of Drop-on-Demand Ink Jets
`Eleven important characteristics of the fundamental
`operation of individual ink jet noZZles have been identi?ed.
`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.
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`The folloWing tables form the axes of an eleven dimen
`sional table of ink jet types.
`Actuator mechanism (18 types)
`Basic operation mode (7 types)
`Auxiliary mechanism (8 types)
`Actuator ampli?cation or modi?cation method (17 types)
`Actuator motion (19 types)
`NoZZle re?ll method (4 t