EP0498291A1 - Structures des éjecteurs pour imprimantes à jet d'encre - Google Patents

Structures des éjecteurs pour imprimantes à jet d'encre Download PDF

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Publication number
EP0498291A1
EP0498291A1 EP92101474A EP92101474A EP0498291A1 EP 0498291 A1 EP0498291 A1 EP 0498291A1 EP 92101474 A EP92101474 A EP 92101474A EP 92101474 A EP92101474 A EP 92101474A EP 0498291 A1 EP0498291 A1 EP 0498291A1
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EP
European Patent Office
Prior art keywords
heater
nozzle
ink
nozzles
zbj
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP92101474A
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German (de)
English (en)
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EP0498291B1 (fr
Inventor
Kia Silverbrook
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Canon Information Systems Research Australia Pty Ltd
Canon Inc
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Canon Information Systems Research Australia Pty Ltd
Canon Inc
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Priority claimed from AU89996/91A external-priority patent/AU657930B2/en
Application filed by Canon Information Systems Research Australia Pty Ltd, Canon Inc filed Critical Canon Information Systems Research Australia Pty Ltd
Publication of EP0498291A1 publication Critical patent/EP0498291A1/fr
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/135—Nozzles
    • B41J2/16—Production of nozzles
    • B41J2/1621—Manufacturing processes
    • B41J2/1626—Manufacturing processes etching
    • B41J2/1628—Manufacturing processes etching dry etching
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/135—Nozzles
    • B41J2/14—Structure thereof only for on-demand ink jet heads
    • B41J2/14016—Structure of bubble jet print heads
    • B41J2/14032—Structure of the pressure chamber
    • B41J2/1404—Geometrical characteristics
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/135—Nozzles
    • B41J2/14—Structure thereof only for on-demand ink jet heads
    • B41J2/14016—Structure of bubble jet print heads
    • B41J2/14032—Structure of the pressure chamber
    • B41J2/14056—Plural heating elements per ink chamber
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/135—Nozzles
    • B41J2/14—Structure thereof only for on-demand ink jet heads
    • B41J2/14016—Structure of bubble jet print heads
    • B41J2/14088—Structure of heating means
    • B41J2/14112—Resistive element
    • B41J2/14137—Resistor surrounding the nozzle opening
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/135—Nozzles
    • B41J2/14—Structure thereof only for on-demand ink jet heads
    • B41J2/14016—Structure of bubble jet print heads
    • B41J2/14145—Structure of the manifold
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/135—Nozzles
    • B41J2/16—Production of nozzles
    • B41J2/1601—Production of bubble jet print heads
    • B41J2/1603—Production of bubble jet print heads of the front shooter type
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/135—Nozzles
    • B41J2/16—Production of nozzles
    • B41J2/1621—Manufacturing processes
    • B41J2/1623—Manufacturing processes bonding and adhesion
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/135—Nozzles
    • B41J2/16—Production of nozzles
    • B41J2/1621—Manufacturing processes
    • B41J2/1626—Manufacturing processes etching
    • B41J2/1629—Manufacturing processes etching wet etching
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/135—Nozzles
    • B41J2/16—Production of nozzles
    • B41J2/1621—Manufacturing processes
    • B41J2/1631—Manufacturing processes photolithography
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/135—Nozzles
    • B41J2/16—Production of nozzles
    • B41J2/1621—Manufacturing processes
    • B41J2/1632—Manufacturing processes machining
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/135—Nozzles
    • B41J2/16—Production of nozzles
    • B41J2/1621—Manufacturing processes
    • B41J2/1635—Manufacturing processes dividing the wafer into individual chips
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/135—Nozzles
    • B41J2/16—Production of nozzles
    • B41J2/1621—Manufacturing processes
    • B41J2/164—Manufacturing processes thin film formation
    • B41J2/1642—Manufacturing processes thin film formation thin film formation by CVD [chemical vapor deposition]
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/135—Nozzles
    • B41J2/16—Production of nozzles
    • B41J2/1621—Manufacturing processes
    • B41J2/164—Manufacturing processes thin film formation
    • B41J2/1643—Manufacturing processes thin film formation thin film formation by plating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/135—Nozzles
    • B41J2/16—Production of nozzles
    • B41J2/1621—Manufacturing processes
    • B41J2/164—Manufacturing processes thin film formation
    • B41J2/1645—Manufacturing processes thin film formation thin film formation by spincoating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/17—Ink jet characterised by ink handling
    • B41J2/175—Ink supply systems ; Circuit parts therefor
    • B41J2/17563—Ink filters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/135—Nozzles
    • B41J2/14—Structure thereof only for on-demand ink jet heads
    • B41J2002/1437—Back shooter
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2202/00—Embodiments of or processes related to ink-jet or thermal heads
    • B41J2202/01—Embodiments of or processes related to ink-jet heads
    • B41J2202/11—Embodiments of or processes related to ink-jet heads characterised by specific geometrical characteristics
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2202/00—Embodiments of or processes related to ink-jet or thermal heads
    • B41J2202/01—Embodiments of or processes related to ink-jet heads
    • B41J2202/13—Heads having an integrated circuit

Definitions

  • the present invention relates to ink jet printing and in particular, discloses a semiconductor bubblejet print head.
  • Bubblejet print heads are known in the art and have recently become available commercially as portable, relatively low-cost printers generally used with personal computers. Examples of such devices are those made by HEWLETT-PACKARD as well as the CANON BJ10 printer.
  • Figs. 1 and 2 show schematic perspective views of prior art bubblejet print heads representative of those used by CANON and HEWLETT-PACKARD, respectively.
  • the prior art bubblejet (BJ) head 1 is formed by a BJ semiconductor chip device 2 abutting a laser etched cap 3.
  • the cap 3 acts as a guide for the inward flow of ink (indicated in the drawing by arrows), into the head 1 via an inlet 4, and the outward ejection of the ink from the head 1 via a plurality of nozzles 5.
  • the nozzles 5 are formed as the open ends of channels in the cap 3.
  • the BJ chip 2 are arranged one or more (generally 64) heater elements (not shown) which are energised so as to cause ink to be ejected from each of the nozzles 5 by a bubble of vapourised ink formed within the corresponding channel.
  • the BJ chip 2 also includes a semiconductor diode matrix (not illustrated) which acts to supply energy to the heater elements arranged adjacent the channels.
  • HEWLETT-PACKARD thermal ink jet head 10 as seen in Fig. 2, a two part configuration is also used, however ink enters the cap 12 through an inlet 13 arranged in the side of the cap 12 which supplies an array of nozzles 14 arranged perpendicular to the inlet 13. Ink exits through the face of the cap 12. A flat heater 15 is arranged immediately beneath each nozzle 14 so as to cause ejection of ink from the inlet channel 13 into the nozzles.
  • the present invention relates to bubblejet print technology and deals with one or more of the following aspects:
  • a Z-Axis bubblejet chip (ZBJ chip) is used to describe a chip lying in the x y plane in which ink flows both into and out of the chip in the z direction.
  • Table 1 lists details of ZBJ chips for various applications; and Table 2 lists various fault conditions and their consequence.
  • a Z-axis bubblejet (ZBJ) chip 40 which includes an ink inlet arranged on one (underside as illustrated) plane surface of the chip 40 and a plurality of nozzles 11 which provide for outlets of ink on the opposite side. It is readily apparent from a direct comparison of Figs. 1 and 2 with Fig. .3 that in the ZBJ chip 40, is provided as a single, monolithic, integrally formed structure as opposed to the two part structure of the prior art.
  • the chip 40 is formed using semiconductor fabrication techniques. Furthermore, ink is ejected from the nozzles 41 in the same direction that ink is supplied to the chip 40.
  • a cross-section of a first embodiment of a stationary (i.e. non-moving) ZBJ printhead 50 is shown which is configured for the production of full length A4 continuous tone colour images at an image density of 1600 dpi or 400 pixels per inch.
  • the head 50 is provided with a ZBJ chip 70 having four nozzle arrays, one for each of cyan 71, magenta 72, yellow 73 and black 74.
  • the nozzle arrays 71-74 are formed from nozzle vias 77 with four nozzles per pixel giving a total of 51,200 nozzles per chip 70.
  • FIG. 4 shows the basic nozzle cross-section which is formed in a silicon substrate 76 over which a layer 78 of thermal SiO2 is formed.
  • a heater element 79 is provided about the nozzle 77 which is capped by an overcoat layer 80 of chemical vapour deposited (CVD) glass.
  • CVD chemical vapour deposited
  • Each of the nozzles 77 communicates to a common ink supply channel 75 for that particular colour of ink.
  • the ZBJ chip 70 is positionable upon a channel extrusion 60 which has ink channels 61 communicating with the channels 75 so as to provide for a continuous flow of ink to the chip 70.
  • a membrane filter 54 is provided between the extrusion 60 and the chip 70.
  • Two power bus bars 51 and 52 are provided which electrically connect to the chip 70.
  • the bus bars 51 and 52 also act as heat sinks for the dissipation of heat from the chip 70.
  • Fig. 5 shows a second embodiment of a ZBJ head 200 similar in configuration to that shown in Fig. 4.
  • the head 200 has a ZBJ chip 100 including nozzle arrays 102, 103, 104 and 105 for each of cyan, magenta, yellow and black respectively.
  • the chip 100 has ink channels 101 which communicate with ink reservoirs 211, 212, 213 and 214, respectively for the above colours, in a channel extrusion 210.
  • the channel extrusion 210 has an alternate geometry of higher volumetric capacity than that shown in Fig. 4 for the same size of the chip 100. Also illustrated are tab connections 203 and 204 which connect the power bus bars 201 and 202 to the chip 100. A membrane filter 205 is also provided as before.
  • the head 200 is required to be about 220 mm long, by 15 mm across, by 9 mm deep. Using the foregoing as a standard arrangement, many configurations of ZBJ heads are possible. The actual size and the number of nozzles per chip depends solely on the required performance of the printer application.
  • Table 1 lists seven applications of ZBJ printheads and the various requirements for each application considered necessary.
  • Application one is considered suitable for low cost full colour printers, portable computers, low cost colour copiers and electronic still photography.
  • Application two is considered suitable for personal printers, and personal computers, whilst application three is useful in electronic still photography, video printers and workstation printers.
  • the fourth application finds use in colour copiers, full colour printers, colour desktop publishing and colour facsimile.
  • the fifth application is for a monochrome devise which sees application in digital black and white copiers, high resolution printers, portable computer's, and plain paper facsimiles.
  • Applications six and seven show respectively high speed and medium speed A3 continuous tone applications useful in colour copiers and colour desktop publishing.
  • the high speed version of application six finds use in small run commercial printing and the medium speed version in colour facsimile.
  • the ZBJ chip 100 has four nozzle arrays 102-105, each comprising four rows of nozzle vias 110 (Figs. 6-9).
  • the nozzle vias 110 are formed by etching through a substrate 130 of the chip 100.
  • the substrate 130 is generally about 500 microns deep and depending on the required application, can be 220 mm long by 4 mm wide.
  • Figs. 6 to 9 illustrate the etching of the nozzle vias 110 through the substrate 130. So that the ZBJ chip 100 can eject a drop of 3 pl, it is necessary for the diameter of each nozzle 110 to be approximately 20 microns.
  • a four stage process is used commencing with a 500 micron deep substrate 300 having an overlying glass (SiO2) layer 142 enclosing a heater 120 within as seen in Fig. 5.
  • the step as seen in Fig. 6 is a plasma etch of a 20 micron straight-walled round hole, through the glass overcoat 142 and at least 10 microns into the substrate 130. This forms the nozzle tip 111.
  • the next step as seen in Fig. 7 requires the etching of a large channel (approximately 100 microns wide by 300 microns deep) in the rear of the chip 100.
  • the neat step, as seen in Fig. 8, is to print nozzle barrel patterns at the bottom of the channels 114 formed in Fig. 7.
  • the nozzle barrels 113 are approximately 40 microns in diameter and are plasma etched to within 10 microns of the front of the chip 100. As the an isotropic plasma etch is relatively non-selective, this method cannot be used to etch the entire cavity without also etching through, and destroying the heater 120.
  • an isotropic etch is used on all exposed silicon to a depth of 10 microns from the front of the chip 100.
  • This step acts to widen the nozzles 110 and undercut the SiO2 layer 142 containing the heater 120.
  • This step forms the nozzle cavity 112.
  • the step also ensures that the tip 111 join the barrel 113 without risking plasma etched damage to the heater 120.
  • the front to back surface etching should be aligned to better than 10 microns and the etch depth control should also be better than 10 microns.
  • the complete nozzle via 110 is formed including its tip 111, cavity 112, barrel 113 and channel 114.
  • nozzle tip 11 which acts as a thermal chamber
  • nozzle barrel 113 which acts as a thermal chamber
  • Prior art integrated bubblejet heads manufactured by Canon use hafnium boride (HfB2) as the heater element 120.
  • the present Canon BJ10 printer has heater parameters selected for a drop size of 65 pl.
  • the drop size of 3 pi as used in the preferred embodiments of the present invention, being substantially smaller, retires re-dimensioning of the heater configuration. So as to ensure that high temperatures are reached, whilst maintaining heater resistance and minimising overall size, a serpentine design as seen in Fig. 10 can be used.
  • the heater 120 comprises two heating elements which take the form of a main heater 121 and a redundant heater 122 arranged about, and surrounding the nozzle tip 111.
  • the redundant heater 122 is provided so as to increase the fault tolerance of the ZBJ chip 100 thereby increasing the yield of the manufacturing process.
  • This configuration of the heaters 120 contrasts with the prior art where, because of the two part structure, the heaters reside on the BJ chip which forms only one of the channel walls.
  • Fig. 11 shows a cut-away section of the nozzle via 110 of Figs. 6 to 10.
  • the relative dimensions of the heater 120 and nozzle tip 11 can be assessed.
  • Fig. 12 represents a cross-section along the lines A-A'-B- B' of Fig. 10 of a single, complete, nozzle thermal chamber.
  • the substrate 130 is generally a silicon wafer approximately 200 microns thick (thinned from a 500 micron wafer by back-etching after high temperature processing).
  • the substrate 130 in addition to providing ink paths and thermal paths for waste heat, also acts as a semiconductor substrate for driver electronics which connect to the heater 120.
  • a thermal insulation layer 132 is provided as a 0.5 micron layer of thermally grown SiO2.
  • the layer 132 has several functions including providing electrical insulation for the heater 120 from an overlying passivation layer 144, providing mechanical cushioning of the heater 120 from the force of a collapsing vapour bubble, and acting as an integral part of a MOS driver circuit (to be later described).
  • the thermal layer 132 is preferably manufactured to be as thin as possible without sacrificing reliability.
  • the layer 132 is thermally grown SiO2 and not CVD SiO2, it has no pin holes. Thus, it is possible for it to be thinner than the corresponding layer on prior art bubblejet heads.
  • the heater 120 is a 0.05 micron layer of hafnium boride or other compound of group IIIA to VIA metal borides. This provides a high electrical resistance element to convert an electrical driving pulse to a thermal pulse.
  • the very high melting point of HfB2 (3100°C) means that there is a substantial margin in the actual heater temperature.
  • the electrical contact to the heater 120 is provided by a heater contact 123 comprised of 0.5 microns of aluminium. This is formed part of a first metal level 134.
  • the first metal level 134 is a layer of aluminium 0.5 microns thick.
  • the first level 134 is formed at the same time as the contacts 123 to the heaters 120. This layer provides connections between the heaters 120 and the drive electronics (to be described), as well as connections within the drive electronics. It is to be noted that for the colour ZBJ heads described in this specification, there are a large number or nozzles 110 in a small area, requiring a high interconnection density and fine line width. Because of this, interconnection sizes of the order of 2 microns are required.
  • the thickness of the layer 136 is important to the operation of the ZBJ chip 100, as it provides a thermal lag between the heater 120 and a thermal shunt 140, thereby ensuring that the majority of the heat is transferred to the ink 106 rather than to the substrate 130.
  • the interlevel insulator 136 also provides the electrical insulation between the first metal level 134 and a second metal level 138, but in thin role, the thickness is not critical.
  • a second metal level 138 is provided and forms the second level of electrical interconnections as well as the thermal shunt 140.
  • the interconnection density of the high speed ZBJ heads earlier described is high enough to require two levels of metal if 2 micron design rules are used. Other head designs may only require one level of metal. If one level of metal is used, an alternative arrangement for the thermal shunt 140 is required, as this is formed on top of the interlevel oxide 136.
  • the thermal shunt 140 is formed from a disc of aluminium approximately 0.5 microns thick.
  • the shunt 140 is thermally connected to the substrate 130 through vias 410 in the thermal layer 132 and the interlevel layer 136, but serves no electrical purpose.
  • the purpose of the thermal shunt 140 is to couple waste heat from the heater 120, to the substrate 130 at a controlled rate. The heat must be substantially removed in the period between heater energisation pulses, so that the quiescent temperature of the ink 106 remains low.
  • the thermal shunt 140 be formed at the same time as the second metal level 138. This is possible if the thickness of the thermal shunt 140 corresponds to that of the second metal level 138.
  • the required thickness is determined by the quality of heat coupling between the thermal shunt 140 and the heater 120. The actual amount of heat coupling required is best determined by accurate computer modelling for the particular nozzle geometry used. The amount of heat coupling can be varied from that illustrated (in Figs. 32-35 to be described hereafter) either by etching holes in the heat coupling disc of the shunt 140 so as to decrease the thermal conductivity.
  • the thermal coupling can be increased by increasing the thickness of the shunt 140 and/or replacing it with a material of higher thermal conductivity, such as silver.
  • thermal shunt 140 Another purpose of the thermal shunt 140 is to prevent a overcoat 142 formed of thick CVD glass from being heated. This will slow CVD carrier gas diffusion through the thick layer 142, and therefore slow the formation of gas bubbles which can destroy the heater 120.
  • the overcoat 142 is a thick layer of CVD or PECVD glass, and has three functions. Firstly, to provide the nozzle for ink ejection, secondly to provide mechanical strength to resist the shock of exploding or collapsing vapour bubbles, and thirdly to provide protection against the external environment.
  • the thickness of the overcoat 142 can be about 4 microns although this can be substantially thicker to provide adequate nozzle length.
  • a passivation layer 144 is provided by means of a 0.5 micron layer of tantalum, or other materials, which is conformably coated over the entire structure of the chip 100 to provide chemical and mechanical protection thereto.
  • the ink 106 in Fig. 12 also acts to remove waste heat.
  • a 3 pl drop of ink generally removes 13 nJ of heat for each degree celsius that its temperature has been raised.
  • a heater 440 has a main heater 441 and a redundant heater 443 each of which are annular and surround the nozzle 445 out of which an ink drop 446 is ejected.
  • the heaters 441 and 443 are made of deposited HfB2 and are interlaced by overlapping aluminium connections 442 and 443 (respectively). With this configuration, the heater 440 surrounds the underlying thermal cavity 447 and can therefore produce an annular ink vapour bubble (see Figs. 24 to 31). This bubble therefore tends to exert near equal pressure to all sides of the ink drop 446. Because the main heater 441 and redundant heater 443 are identical with respect to shape and location, they have identical drop ejection characteristics. The heaters 441 and 443 are also slightly eccentric with respect to the nozzle 445 and so the drop ejection angle does not change significantly if the main heater 441 fails and the redundant heater 443 is used.
  • FIG. 12 illustrates a nozzle 110 having a cylindrical cavity 112 and narrower tip 11, forming an underlying thermal chamber or cavity 115
  • various alternative nozzle geometries are also useful, some of which are illustrated in Figs. 14 to 23.
  • the thermal chamber 115 which surrounds the nozzle tip 111 is arranged as a cylinder, with the heater 120 deposited in the walls of the cylinder.
  • This arrangement has several disadvantages, including:
  • the thermal chamber 115 is arranged as a cone. This is to allow the heater 120 to be etched to increase its resistance. This arrangement has the following difficulties:
  • Fig 16 shows a quasi-hemispherical chamber in which the heater 120 is formed on a frusto-conical section which faces into a substantially hemispherical chamber.
  • Figs. 17 to 22 show six preferred nozzle structures which permit monolithic construction, a small drop size of 3 picolitres thus permitting 1600 dpi printing, fault tolerant heater design, nozzle spacing anywhere on the surface of the substrate and permitting use in multi-colour print devices. Further, more detailed discussion of the fabrication of the following nozzle structures can be found later in this document.
  • Fig. 17 illustrates a substantially hemispherical thermal chamber 115 and which is formed by applying an undercutting isotropic plasma etch of silicon before reactive ion etching (RIE) of the nozzle barrel 113.
  • This configuration is characterised by a reverse action in which the formation of the bubble 116 is in the direction opposite to the ejection of the ink drop 108.
  • the thermal shunt 140 conducts heat away from the nozzle area into the substrate 130 to reduce the time taken for the thermal chamber 115 to cool sufficiently prior to the ejection of the next ink drop 108.
  • This configuration has advantages of planar construction of the heater 120 whereby accurate control of the heater shape and size can be achieved. Also, the thermal coupling between the heater 120 and the ink 106 is significant, because the heater 120 is isolated from the ink 106 by the thermal SiO2 layer 132 which is more thermally conductive than CVD glass. Also, this layer can be manufactured thinner than a corresponding layer of CVD glass, as it is not prone to pinholes. Depending on the slope of the barrel 113 as it enters the thermal 115, and the contact angle of the ink with the passivation layer 144 (see Fig. 12), this nozzle geometry will permit automatic filling by capillary action.
  • Fig. 18 is similar to the configuration of Fig. 17 except that in this geometry, the direction of flow of ink 106 through the chip 100 is reversed giving a reversed nozzle arrangement 485 in which bubble formation is in the same direction as ink drop ejection.
  • ink 106 enters the nozzle passageway through an aperture 481 and a meniscus 107 is formed at the nozzle tip 486 boundary between the barrel 487 and the channel 489. Formation of bubbles 116 acts to expel an ink drop 108 through the channel 489 and onto a medium such as paper 220.
  • the configuration of the reverse nozzle arrangement 485 differs in one significant way from the earlier configurations described.
  • the earlier configurations e.g. Fig. 17
  • a thermal shunt 140 which acts to shunt heat away from the heater 120 and into the substrate 130.
  • immediately adjacent the heaters 120 is an underlying reservoir of ink 106.
  • a thermal diffuser 491 is used to increase the area of heat transport from the heater 120 through the overcoat 142 and into the ink 106 reservoir.
  • heat conductive path is much shorter than that of Fig. 17, greater heat dissipation can be achieved.
  • heat dissipation can be further enhanced by re-circulating the ink 106 through a heat exchanger using a supply pump (not illustrated).
  • This configuration has the advantages of planar construction, good thermal coupling and heat dissipation. Also, bubble direction is in the direction of ink ejection which reduces kinetic losses.
  • a disadvantage of this configuration is that the nozzle is not self priming, and must be initially primed using positive pressure. Once primed, the shrinking bubble will draw ink into the thermal chamber 488 after the drop 108 has been fired. Also, the cantilevered section supporting the heaters 120 must be sufficiently thick to withstand the shock from collapsing bubbles 116.
  • a nozzle arrangement which includes a trench implanted heater 493.
  • the nozzle cavity 112 is formed as a straight cylinder communicating with the nozzle barrel 113 and the optionally etched nozzle channel 114.
  • An annular trench 492 is etched into the silicon, and a layer of SiO2 is grown adjacent and about the nozzle cavity 112.
  • the annular heater 493 is plated on the trench 492 which acts to form vapourised bubbles 116 which expand across the cavity 112 transverse the direction of drop ejection. Advantages of this configuration include good thermal coupling and self-priming.
  • Disadvantages includes poor heat dissipation because liquid cooling by forced ink flow is not effective as the bulk of the ink is isolated from the bubble generating surface by 600 microns of substrate 130. Also, it is difficult to obtain adequate nozzle length as this must be generated by very thick layers of CVD glass forming the overcoat 142. Additionally, bubble formation being transverse permits non-optimal motion coupling. Also, thermal conduction into the substrate 130 is high causing heat to be wasted therethrough. Finally, the length of the heater 493 is constrained by the circumference or the nozzle, or half the circumference if fault tolerance is employed, and so it is difficult to obtain a high resistance heater 493.
  • Fig. 20 illustrates the annular trench configuration of Fig. 19 shown in the reversed arrangement.
  • the annular trench 492 extends towards the nozzle tip 486 as does the diffused heater 493 therein.
  • a thermal diffuser 491 is also provided in the previous manner.
  • the nozzle length can be easily varied. Advantages of this configuration reside in thermal coupling, case of heat dissipation, self priming and ease of manufacture. Disadvantages include the bubble direction being transverse to the direction of ink drop ejection, and difficulty in controlling the length of the heater 493. Also, thermal conduction to the silicon substrate 130 is high which causes heat to be wasted.
  • Fig. 21 shows a further configuration utilising an elbow heater.
  • a cylindrical nozzle passageway is formed between the nozzle tip 111 and the barrel 113.
  • Thermally grown SiO2 is provided as a layer 494 which extends into the barrel 113.
  • An elbow oriented heater 495 is then plated onto the layer 494 and an electrical contact 496 made on the top surface of the heater 495.
  • Overcoat layer 142 of CVD SiO2 is then provided over the contact and heater and extends into the nozzle barrel 113. Advantages of this configuration are self priming and thermal insulation of the heater 495 from the substrate 130.
  • Disadvantages include poor heat dissipation, difficulties in controlling the nozzle length by varying the thickness of the overcoat 142, transverse bubble direction, poor thermal coupling due to the heater 495 being isolated from the ink 106 by a layer of amorphous CVD glass, difficulties in controlling heater length, and manufacturing complexity (described later).
  • Fig. 22 illustrates the reverse arrangement of the elbow connected heater 495 which is manufactured in a similar manner.
  • Advantages include heat dissipation through the ink reservoir, self priming and the heater 495 being thermally insulated from the substrate 130.
  • Disadvantages include transverse bubble direction, poor thermal coupling through the amorphous CVD glass between the heater 495 and ink 106, and constraints to the heater length.
  • Fig. 23 illustrates a nozzle arrangement similar to that of Fig. 18, however the relative sizes of the nozzle aperture 484 and the nozzle tip 486 have been varied to improve capillary action for the filling of the nozzle and the formation of the meniscus 107.
  • One disadvantage of the configuration of Fig. 18 is that the nozzle aperture 484 and the nozzle tip 486 have equal diameters. The diameter of the nozzle tip 486 varies depending on a number of design criteria such as the desired drop size.
  • the ink 106 In order to prime the nozzle and provided the meniscus 107 as illustrated, the ink 106 must flow through the aperture 484 but then stop at the tip 486. Generally, if both are the same size, the ink will either form a meniscus at the aperture 484, or drip through the tip 486 depending on the priming pressure. Neither of these conditions are desired. What is specifically desired is that the aperture 484 be of sufficient diameter to allow for priming of the nozzle, and that the tip 486 be of a different, smaller diameter to provide for the formation of the meniscus 107. The nozzle is then primed using a pressure greater than the "bubble pressure" of the aperture 484, but less than the "bubble pressure" of the nozzle 486.
  • the configuration of Fig. 23 which illustrates a suitable arrangement wherein the diameter of the aperture 484 is approximately 50% larger than that of the tip 486. This configuration also provides for accurate control of the drop size whilst maintaining high refilling rates of the nozzle.
  • the operation of the ZBJ chip 100 differs from that of prior art bubblejet heads through the use of an alternate drop ejection mechanism which is illustrated in Figs. 24 to 31.
  • a single nozzle 110 of the ZBJ print head 100 is shown in its quiescent state where the heater 120 is off.
  • Ink 106 within the nozzle 110 forms a meniscus 107.
  • the heater 120 is turned on thus heating the surrounding substrate 130 and thermal layer 132 which in turn heats the ink 106 within the nozzle 110. Some of the ink 106 evaporates to form small bubbles 116.
  • the heater 120 is turned off which acts to contrast the bubble 116 and draw ink 106 from the drop 108 that is formed.
  • the ink 106 oscillates, and eventually returns to the quiescent state.
  • the oscillating damping time is one factor which determines the maximum dot repetition rate.
  • Fig. 33 illustrates the super heating of ink in which a thin layer of superheated ink 109 forms adjacent the passivation layer 144 within the nozzle cavity 112.
  • the waste heat is removed by three separate paths. Firstly, heat is removed through the ink which acts to raise its temperature slightly. However, the thermal conductivity of ink is low, so the amount of heat removed by this path is also low.
  • the walls of the nozzle 110 are made of silicon from the substrate 130, and have high thermal conductivity, heat dissipation through the walls is fast. However, not all of the bubble 116 will be in contact with the side walls of the nozzle 110.
  • Fig. 34 illustrates the heat flow from the cooling bubble 116 as described above.
  • Fig. 35 also shows waste heat removal paths 125 in which heat will flow through the substrate 130 as the main thermal conduit away from the heater 120. Some of this heat will flow back into the ink 106 and eventually be ejected with subsequent drops 108. The remainder of the heat will flow through the substrate 130 and into the aluminium heat sink (51,52), seen in Fig. 4.
  • Fig. 36 illustrates the macroscopic heat dissipation for the ZBJ head 200 with 51,200 nozzles printing four colour. If the heater action does not raise the average temperature of the entire head assembly 200 more than about 10.C to 20.C above that of the incoming ink 106, it is not necessary to provide an external cooling mechanism. In this manner, the ZBJ head 200 can be effectively cooled by a steady flow of ink 106 from ink reservoirs 215, 216, 217 and 218 as illustrated. The quantity of ink flow is in direct proportion to the heat generated, as ink 106 is expelled every time the heaters are turned on.
  • nozzle efficiency thermal and the substantially smaller kinetic output compared with electrical input
  • more heat will be generated than can be expelled with the drops without raising the ink temperature excessively.
  • other heat sinking methods such as forced air cooling or liquid cooling using the ink
  • the operating temperature of the ZBJ heater elements 120 is above 300°C. It is important that the active elements (drive transistors and logic) of the ZBJ chip 100 do not experience this temperature extreme. This can be achieved by locating the drive transistors and logic as far from the heater elements 120 as possible. These active elements can be located at the edges of the chip 100, leaving only the heaters 120 and the aluminium connecting lines in the high temperature region.
  • a full colour ZBJ print head 200 has four ink channels, one for each of cyan 211, magenta 212, yellow 213 and black 214. These channels 211-214 are formed as an aluminium extrusion 210 and are filtered and sealed against the back of the ZBJ chip 100.
  • the ink channels 211-214 of Fig. 37 are not sufficient to provide adequate ink flow.
  • the extrusion profile of Fig. 38 can be used so as to increase the volume of flow.
  • a 10 micron absolute membrane filter 205 is provided between the ink channel extrusion 210 and the ZBJ chip 100 so as protect against ink contamination. If the membrane filter 205 is compressible, then it can also form as a gasket to prevent ink flow between the four colours.
  • the edges of the head assembly 200 are preferably sealed to prevent gas ingress. For the above configuration, a manufacturing accuracy of approximately ⁇ 50 microns need only be maintained.
  • the ZBJ chip 100 is susceptible to blockage by particulate contamination of the ink 106. Any particle of a size between 20 microns and 60 microns will permanently lodge in the nozzle cavity 112, as it cannot be ejected with the ink drop 108.
  • a filter such as the membrane filter 205, is included in the ink path to remove all particles larger than 10 microns. This can be a 10 micron bonded fibreglass absolute filter and preferably has a relatively large area to allow sufficient ink flow. This is seen in Figs. 35 and 44.
  • the continuous tone ZBJ chip 100 with four nozzles 110 per pixel has a degree of tolerance of blocked nozzles 110.
  • a blocked nozzle 110 will result in a 25% reduction of colour intensity for that pixel rather than a complete absence of colour.
  • cap and substrate are made of differing materials.
  • One solution to this problem is to make the cap out of the same material as the substrate, usually silicon. Even if this is done, differences in temperature between the silicon substrate and the silicon cap (caused by waste heat from the heaters) can be sufficient to cause mis-registration.
  • the ZBJ chip 100 does not suffer from these problems, as the heaters 120, nozzles 110 and ink paths 101 are all fabricated using a single silicon substrate 130. Nozzle to heater registration is determined by the accuracy of the photolithography with which the ZBJ chip 100 is manufactured. Due to the relatively large feature sizes of this configuration, there is little difficulty in ensuring that the nozzles are correctly aligned as the ZBJ chip 100 is a monolithic chip capable of being manufactured using a 2 micron semiconductor processes.
  • 16 drops per pixel are used to create an image density of 400 pixels per inch. This gives 16 levels of gray tone per pixel.
  • the tonal subtleties required to produce continuous tone image can be produced by standard digital dot or line screening method or by error diffusion of the least significant 4 bits of an 8 bit colour intensity value. This results in a perceived colour resolution of 256 levels per colour, while maintaining a spacial resolution of 400 pixels per inch.
  • Fig. 39 illustrates the ink drop positions for one pixel of a four nozzle per pixel configuration.
  • the drops are patterns to fill the pixel in a 4 ⁇ 4 array of dimensions 64 mm ⁇ 64 mm.
  • Horizontal spacing is provided by the spacing between the nozzle 110, and vertical spacing is provided by paper movement. This arrangement provides sufficient linearity in the relationship between the number of drops and the colour intensity.
  • Four nozzles per pixel also allows a print speed four times faster than that of one nozzle per pixel design, with only slightly larger chip area. The effect of a blocked or defective nozzle is also limited by a reduction in colour by 25%.
  • Fig. 40 shows a single nozzle type and the ink drop positions for one pixel.
  • the vertical drop spacing is provided by paper movement. If sixteen drops are deposited in a 64 micron pixel, drops are spaced at 4 microns. The pixel is filled horizontally by the flow of wet ink from overlapping drops.
  • This arrangement has the disadvantages of severe non-linearity in the relationship between the number of drops and the colour intensity, and a lower print speed.
  • the advantage is a lower cost of manufacture than that of the four nozzle per pixel embodiment.
  • Fig. 41 shows the use of a head timing which is divided into 32 different time slots, or "firing orders" each separated by 6.25 microseconds. This produces a repeated cycle of 200 microseconds before the same nozzle as fired again.
  • Movement of the print medium e.g. paper 220 in Fig. 18
  • the print medium e.g. paper 220 in Fig. 18
  • the nozzles 110 can readily be skewed to cancel any dot skew caused by paper movement, however this skew will be very small.
  • FIG. 42 this shows a possible nozzle layout for a full colour ZBJ head with one nozzle per pixel and 16 drops per pixel.
  • Horizontal spacing of the nozzles 110 is 1 pixel (64 microns).
  • the nozzles 110 are placed in a zig-zag pattern to maintain spacing of at least 80 microns between nozzle barrels 113, in order to maintain the mechanical strength of the head.
  • Such a head design can be produced with three micron lithography.
  • Fig. 43 shows a nozzle layout for the full colour ZBJ head 200 with four nozzles 110 per pixel, each firing four times per pixel to give 16 drops per pixel.
  • Horizontal spacing of the nozzles 110 is 16 microns (a quarter of a pixel).
  • the nozzles 110 are arranged in 8 rows in zig-zag pattern to maintain at least 80 microns spacing therebetween.
  • the nozzles 110 of the adjacent rows are also positioned (offset to one another) to compensate for any skew caused by paper movement, indicated by the arrow 222.
  • This head design requires 2 micron lithography for nozzle interconnects and drive circuitry.
  • the head assembly 200 must deal with several specific requirements: ink supply; ink filtration; power supply; power dissipation; signal connection; and mechanical support.
  • the ZBJ head 200 with 51,200 nozzles, each of which can eject a 3 pl ink drop every 200 microseconds, can use a maximum of 1.28 ml of ink per second. This occurs when the head 200 is printing a solid four-colour black. As there are four colours, the maximum flow is 0.23 ml per colour per second. If the ink speed is to be limited to around 20 mm per second, then the ink channels 211-214 must have a cross- sectional area of 16 mm2 each.
  • any particles carried in the ink that are less than 60 microns in diameter will be carried into the nozzle channel 114. Any of these particles which are greater than 20 microns in diameter cannot be ejected from the nozzle 110. Even if pre-filtered ink is supplied to the user, there is a possibility of particle contamination when the ink is re- filled. Therefore, the ink must be effectively filtered to eliminate any particles between 20 and 60 microns.
  • the peak current consumption or the full width colour ZBJ head 200 is about several amperes. This must be supplied to the entire length of the chip 100 with insignificant voltage drop. Also, the ZBJ head has more than 35 signal connections, the exact number depending upon the chosen circuit design, and accordingly insignificant voltage drop is also required.
  • the ink channel extrusion 210 has three functions: to provide the ink paths and keep the four colours separate; to provide mechanical support for the ZBJ chip 110; and to assist in dissipating the waste heat to the ink 106.
  • the ink channels extrusion 210 be extruded from aluminium, and anodised to provide electrical insulation from the busbars 201 and 202. Manufacturing accuracy of the extrusion 210 need only be maintained to approximately ⁇ 50 microns, as the extrusion 210 is not in contact with the nozzles 110. The edges of the channel extrusion 210 should be sealed against the ZBJ chip 100 to prevent air from entering the head assembly 200. This can be achieved with the same epoxy as that used to glue the assembly 200.
  • Fig. 44 illustrates an exploded perspective view of a preferred construction of a high speed full colour ZBJ assembly 200.
  • the filter 205 is preferably a 10 micron (or finer) absolute filter such as a filterite "Duofine" (Trade Mark) bonded fiberglass filter.
  • the surface area of this filter through which the ink must flow is 528 mm2. With an ink flow rate of 1.28 ml per second, the ink must pass through the filter at a velocity of 2.4 mm per second.
  • the filter 205 is compressible, it can also farm a gasket to prevent pigment flow between the four colours.
  • the ZBJ chip 100 can he glued to the extrusion 210 under pressure. Alternatively, a silicone rubber seal can be used. In this case, care must be taken not to contaminate the ink channels 211-214.
  • One way of supplying the necessary power to the chip 110 is by power connections which run the full length of the chip 110. These can be connected using tape automated bonding (TAB) to the busbars 201 and 202 which form part of the head assembly 200.
  • TAB tape automated bonding
  • the signal connections to the ZBJ chip 100 can be formed using the same TAB tapes as are used to supply power to the ZBJ chip 100.
  • the busbars 201, 202 can be configured as heat sink elements surrounding the extrusion 210.
  • the ink drop 108 does not necessarily exit perpendicular to the ZBJ head surface.
  • the ink drop 108 can be deflected by the shock waves of the expanding bubble at different angles depending on whether the main 121 or redundant 122 heater was fired.
  • Such a configuration is illustrated in Figs. 45 and 46 respectively which should be viewed in conjunction with Figs. 10 and 12.
  • the angle and degree of the deflection 153 and 154 will depend upon the exact geometry of the ZBJ nozzle 110, and the mode of propagation of the bubble's 116 shock wave through the ink 106.
  • the edit angle of the drop 108 is not important in itself. However, any difference between the exit angle of the drop fired by the main heater 121 and one fired by the redundant heater 122 will degrade the image quality slightly.
  • the above can be reduced in two ways: Firstly by positioning the head 200 closer to the paper 220 to reduce the distance between the two spots on the paper 220, and secondly by delaying the time of the redundant nozzle firing so that the paper movement cancels the deflection angle 153 or 154. This requires that the main and redundant heaters be aligned in the direction of paper movement 222.
  • the A4 full width continuous tone ZBJ head 200 has a high current consumption of several amperes when operating. The distribution of this current to and across the chip 100 is not possible using standard integrated circuit construction. However, the geometry of the ZBJ chip 100 leads to a simple solution. The entire edge of the chip 100 can be used to supply power, with connections being made to a wide aluminium trace along both of the long edges of the chip 100. Power can be supplied by the busbars 201 and 202 along both sides of the chip 100 connected to the chip by tape automated bonding (TAB), compressible solder bumps, spring leaf connection to gold plated traces, a large number of wire bonds, or other connection technology.
  • TAB tape automated bonding
  • Fig. 41 illustrates one method of TAB connection along the length of the ZBJ chip 100 with the connections shown in magnified detail.
  • Fig. 48 shows a magnification of an alternate arrangement using a knurled edge for multipoint contacts.
  • the heatsink/busbar (51,52) (201,202) can readily be made larger, or of different shape, or of different materials without affecting the concept of the ZBJ head 200. Forced air, heat pipes or liquid cooling can also be used. It is also possible to reduce the current consumption by reducing the duty cycle of the nozzle 110. This will increase the print time, but reduce the average power consumption. The total energy required to print a page will not be affected.
  • the full length full colour head can have a power dissipation of up to 500 watts when all nozzles are printing, depending on the nozzle efficiency.
  • the scanning bubblejet head used in Canon's BJ10 printer has 64 nozzles energised by an array of heaters 6 which are shown in Fig. 49. These are multiplexed into an 8 ⁇ 8 array using diodes 8 integrated onto the chip. External drive transistors (not illustrated) are used to control the heaters 6 in eight groups of eight heaters 6.
  • the prior art approach has several disadvantages for large nozzle arrays. Firstly, all of the heater power must be supplied via the control signals and this can require a large number of relatively high current connections. Also, the number of external connections becomes very large.
  • the preferred embodiment of the ZBJ chip 100 includes drive transistors and shift registers on the chip 100 itself. This has the following advantages:
  • Fig. 50 shows the logic and drive electronics of the ZBJ chip 100 with 32 parallel drive lines, corresponding to the 32:1 nozzle duty cycle.
  • the enable signals provide the timing sequence, firing each of the 32 banks of nozzles 110 in turn.
  • the enables can be generated on-chip from a clock and reset signal.
  • Vdd is 15 volts and Vss is tied to a clean ground point.
  • V+ and ground have noise of up to several amperes, so may not be suitable for logic even though they are supplied to the chip 100 at a very low impedance.
  • a heater driver 124 for two nozzles 110 Shown in Fig. 50 is a heater driver 124 for two nozzles 110.
  • the drivers 124 consist of two individual drivers 160 and 165 for two nozzles (without fault tolerance) showing the data connections of the shift registers.
  • Each heater driver 160, 165 consists of four items:
  • the clock period is the game as the pulse width, because 32 bits of data must be shifted in each shift register between nozzle firings, and there is a 32:1 duty cycle.
  • the circuit of Fig. 50 is only suitable for a ZBJ head with less than 1,024 nozzles. However, where there is only a small number of nozzles an active circuit provides little advantage, and a diode matrix can be used.
  • the clock required to shift all of the data to the appropriate nozzles requires a period shorter than the heater pulse.
  • 51,200 bits of information must be shifted into the head in 200 microseconds. This requires a clock rate of about 8 MHz.
  • the data at the shift registers 161,166 therefore only need be valid for 125 nS but is required for the full duration of the 6.25 microsecond heater pulse. Disclosed herein are two solutions to this problem, one being a transfer register and the other being clock pauses.
  • Fig. 51 illustrates the addition of a transfer register 172 to a main heater drive 170 having componentry otherwise corresponding to that of Fig. 50.
  • This arrangement provides a simple solution to the above problem but has the disadvantage of increasing the amount of circuitry on the chip 100. 1,600 bits of data are shifted into each shift register 171 at 8 MHz. When the enable pulse occurs, the data is parallel loaded to the transfer register 172 where it is stable for the duration of the heater pulse.
  • An alternative which avoids the extra transistors of the transfer register 172 is to introduce pauses into the clock stream for the duration of the heater pulse, so that the data does not change during the pulse.
  • This is illustrated in Fig. 52 and in this case, the 1,600 bits of data are shifted into the register at a slightly higher rate - 8.258 MHz -after which there is a pause in the clock for 6.25 microseconds, the period of heater pulse.
  • Each of the 32 rows of heaters fire at different times.
  • the clocks for each row can be simply generating by gating the constant 8.258 MHz clock with the heater enable pulses.
  • Fig. 53 illustrates one stage of a ZBJ drive circuit 177 which incorporates clock pauses.
  • An AND gate 178 connects between the clock and Enable lines and drives the CLK inputs of the shift registers 161 (and 166 not illustrated but connected at 179).
  • a simple clock regeneration scheme 180 including a chain of shift registers 181 each supplying a corresponding heater driver 124. Included in the clock line are Schmitt triggers 182 equally spaced depending on the permissible fanout. As seen, where a Schmitt trigger 182 occurs in the chain, the next corresponding shift register 181 is input not from the shift register 181 immediately preceding it in the chain, but from the one before that. This compensates for the delay imposed by the Schmitt trigger 182.
  • T PD propagation delay
  • T PLH -T PHL rise and fall times
  • the actual pulse width generated by the monostables 183 is not critical. It must be longer than the minimum pulse width required by the shift registers 181 (about 10 nS), and shorter than the clock period (125 nS). This tolerance is important to allow for the inaccuracy of component values in monolithic circuits.
  • the full colour ZBJ head 200 requires a data rate of 32 MBytes per second (8 MHz average clock rate ⁇ 32 bits). This data must be delayed by up to 7,600 microseconds, and requires nearly 1 megabit of delay storage. If the clock pause system described earlier (Fig. 53) is used to reduce the logic on the ZBJ chip 100, then data must also be presented to the ZBJ chip 100 with a complex timing scheme.
  • Fig. 56 is a block diagram of an overall data driving scheme for the full colour ZBJ head 200 in which an image data generator 300, such as a computer, copier or other image processing system, outputs colour pixel image data on a 32 bit bus 301.
  • the colour pixel image data is normally supplied in raster format (cyan, magenta, yellow and black (CMYK)) with components for each colour being provided simultaneously on the bus 301. Because it is not possible for the nozzles for each colour to sit one on top of the other for simultaneous printing, the different colour data must be appropriately delayed prior to being supplied to the head 200.
  • the colour data produced by the computer 300 on the bus 301 is digital data at 1600 dpi with pre-calculated screen or dithering simulating 400 dpi continuous tone colour image.
  • the bus 301 is divided into blocks of its component colours (cyan, magenta, yellow and black) each of which is respectively input to the ZBJ head 200.
  • the magenta, yellow and black data are delayed by respective line 303, 304 and 305 because these colours are printed sequentially after cyan for each pixel across the head 200.
  • An address generator 302 is used to sequence colour data through the line delays 303- 305.
  • a clock 306 of 8,258 MHz is used to sequence all pixel data and is also supplied to the head 200, which also has a number of power connections 307 as illustrated.
  • the 10, 20 and 30 line delays are formed using three standard 64 K ⁇ 8 SRAMs with a read/modify/write cycle time of less than 120 nS. This is achieved by reading and then writing the SRAMs with the data, while incrementing the address modulo 16,000, 32,000 and 48,000 respectively.
  • the address generator 302 is a simple modulo 16,000 counter, with the two most significant bits of the address of each SRAM generated separately.
  • a ZBJ data phaser ASIC 310 is provided to buffer each nozzle array input so as to reduce system complexity.
  • a single ASIC can be constructed which can be used to provide delays for the 8 bits of any of the four colours.
  • Fig. 57 illustrates a block diagram of a data phaser 310 suitable for the nozzle arrangement in the four nozzle per colour example earlier described. If other nozzle arrangements are used, the length of the delays must be altered to suit.
  • the 50 clock delays 314,315,316 are selectable via a colour select input 313 and are included to allow the same chip 310 to be used for any of the four colour components.
  • the colour select 313 operates a multiplexor which can select data output from any one of the delays 314-316 or directly from the data input 312.
  • the ASIC 310 of Fig. 57 has a very simple design, but requires around 56 Kbits of data storage. It is therefore most suited to standard cell or data-path compilation techniques.
  • the data connections 327 to the ZBJ head relate to the firing order, which determines the length of the delay required.
  • An enable pulse generator 326 provides enable pulses for the heater drivers 124 (previously described).
  • a target assumed for each head is about USS100 or less in volume with a mature process.
  • the ZBJ head 200 is essentially a single piece construction and the head cost will consist almost entirely of the ZBJ chip 100 itself.
  • the ZBJ chip 100 cost is determined by processing cost per wafer, number of heads per wafer, and yield. Assuming that the processing costs per wafer is about S800, and the number of head per wafer is 25, the pre-yield cost per head is S32.
  • the mature-process yield must be about 30%.
  • the chip area for the full colour full length ZBJ heads 200 is of the order of 8.8 cm2.
  • the fault tolerance redundancy of the ZBJ head is preferably provided to improve the yield. This can allow a large number of defects to exist on the chip without affecting the operation of any of the nozzles. Furthermore, it is not necessary to incorporate 100% redundancy, but it is necessary to reduce the non-redundant region of the ZBJ head to a size consistent with an adequate yield. The effect of fault tolerance on yield is discussed later in this specification. Even with fault tolerance, there are several factors which can act to reduce yields below reasonable levels. Some of these factors are:
  • fault tolerance is included in the ZBJ chip 100 so as to improve yield as well as to improve head life.
  • the provision of fault tolerance is considered essential so as to achieve low manufacturing costs of the ZBJ chips 100.
  • the fault tolerance concept described herein is specifically applied to the ZBJ chip 100, the same concept can be used for other types of BJ heads if a configuration with two heaters per nozzle is created.
  • fault tolerance is that chip complexity is doubled. However, due to the topography of the nozzles 110, there is only a slight (about 10%) increase in chip area. The yield decrease this causes is dwarfed by the yield increase provided by fault tolerance.
  • the ZBJ system described herein implements fault tolerance by providing two heater elements 121,122 for each nozzle 110.
  • each heater 120 is provided with two heater elements 121,122 on opposite sides of the nozzle 110 and preferably having identical geometries.
  • the heater elements are termed a main heater 121 and a redundant heater 122, as seen in Figs. 58A and 58B, although the configuration of Fig. 13 can also be used. Accordingly, the ink drop fired from the nozzle tip 111 by either heater 121 or 122 is essentially the same.
  • Control of the redundant heater 122 for fault tolerance is provided by sensing the voltage at the drive transistor to the main heater 121 drive.
  • This node makes a high-to-low transition every time the nozzle 110 is fired. Three faults are detected by the behaviour of this node:
  • Fig. 59 illustrates a drive circuit 185,186 for one nozzle of the ZBJ chip 100 with fault tolerance implemented as a digital circuit sampling at the drain of the main heater 121 driver transistor 164.
  • a latch 189 stores the fault condition detected by the node being low when the heater 121 drive is off.
  • the latch 189 outputs to an AND gate 191 which is also supplied with the drive signal of the main heater 121 drive transistor 164, to indicate that the heater 121 should be on.
  • Another AND gate 190 detects the open drive transistor condition.
  • the two AND gates 190,191 are input to an OR gate 192 to control the redundant heater 122.
  • a capacitor 194 and diodes 196 generate a pulse whenever the high-to-low transition of an operational circuit occurs. This pulse inhibits the firing of the redundant heater 122 when the main heater 121 circuit is operational. If the main heater 121 fails, then the redundant heater 122 will fire at the times that the main heater 121 would have fired.
  • Component values are chosen to ensure that the pulse is longer than the heater-on time (6 microseconds) but shorter than the pulse repetition time (200 microseconds). This permits substantial component tolerance.
  • the heaters 121 and 122, the drive transistors 164,193 and associated connections will consume more than 90% of the area of the ZBJ chip 110, so as a substantial degree of fault tolerance can be provided by providing redundancy in just these areas. However, protection is only provided against small area defects. Any defects with a diameter greater than approximately 10 microns will cause failure.
  • Fault tolerance can be readily extended to include 100% redundancy of the electronics of the ZBJ chip 100.
  • tolerance of some faults from defects of up to 600 microns in diameter can be introduced. This is achieved by duplicating the shift registers 181 described earlier, as well as the drive circuitry. As the shift registers 181 do not consume a substantial amount of chip area, the cost increase of this duplication is exceeded by cost decrease from yield improvement.
  • Fig. 61 shows one stage of a ZBJ drive circuit with complete redundancy in which the main drive circuit 187 is duplicated, but with the addition of a circuit (resistor 250 and capacitor 199) which inhibits the firing of the redundant circuit 188 when the main circuit 187 is operational.
  • Fig. 62 shows a simple chip layout of a small length of the ZBJ chip 100, to provide wide area fault tolerance. While large area faults in drive circuitry can be corrected, only small area faults can be corrected in the nozzle area. This is because the main and redundant heaters 121 and 122 must be in the same nozzle 110. However, the nozzle area has no active circuitry and will not be sensitive to faults in most mask layers.
  • a defect which happens to break the shift register chain of either the main circuit or of the redundant circuit will mean that subsequent driver stages will not be fault tolerant. Also, a stuck-high fault in the data sequence of either the main or redundant shift register will result in chip failure, as will a Vss to Vdd short. However, these types of faults represent only a small percentage of possible faults.
  • Each of the conditions indicated in Table 2 are fault tolerant, except where the two main drive tracks are shorted.
  • This can be made fault tolerant by incorporating a fuse between each main drive transistor 164 and its heater 121.
  • the fuse must he highly accurate and must "blow" at twice the heater current but not one times the heater current.
  • a more elegant solution is to interleave the main drive tracks with the redundant drive tracks. This configuration increases the defect size required to short two main drive tracks by a factor of 3. Such an arrangement reduces the defect density for this source by a factor of 9.
  • a redundant nozzle ZBJ chip 450 is shown having a main cyan nozzle array 451, a redundant cyan nozzle array 452, and a similar configuration for each of magenta (453,458), yellow (455,456) and black (457,458).
  • magenta 453,458
  • yellow 455,456
  • black 457,458
  • a main cyan nozzle 451A is fired by a heater 461 energized through a switch 460
  • a redundant cyan nozzle 452A is fired by a similar heater 463 and switch 462.
  • a fault detector 464 which senses a fault in the main cyan nozzle 451A and provides a firing pulse to the switch 462. Because of the physical displacement of the array 452 with respect to the array 451, it is necessary to compensate for time and/or motion of the relative movement of the paper across the chip 450. This is provided by a parallel loading shift register 465 which detects all of the faults occurring in one row of nozzles and shifts the data out as a serial data stream. This data is then delayed by an appropriate number of line delays and placed in a serial to parallel shift register, where it causes the actuation of the redundant heater 463 via the redundant switch 462.
  • System level fault tolerance can be provided in the manner shown in Fig. 67 where two thermal ink jet chips 470 and 475 are arranged side-by-side.
  • the chip 470 acts as a main device with the chip 475 acting as a redundant device thereby the arrays 471-474 being compensated by the arrays 476-479 in the manner described above.
  • each nozzle 480 must connect to it's corresponding nozzle 481 using a fault detector 482 and compensator 483 as before. This can be achieved by shifting the fault data off the main chip 470, delaying it, and using that data to fire the nozzles of the redundant chip 475.
  • the ZBJ chip 100 is very long and thin, and has many holes etched through it, the mechanical strength of the chip 100 is insufficient to allow high yield dicing in the conventional manner.
  • FIG. 68 A simple solution using a diced back etch is illustrated in Fig. 68 where channels 147 are etched in the back surface of the wafer 149, most of the way through the wafer 149.
  • the wafer 149 is then scored 145 on the front surface.
  • the channels 147 can be etched using the same processes that are used to etch the ink channels 101 and nozzle vias 110.
  • the spacing of vias 146 along the dice line 145 can be adjusted to give the optimum trade-off between strength for handling and ease of dicing.
  • tags 148 (Fig. 46) can be left along the edges of the wafers 149. These tags 148 must be diced off before the ZBJ chips 100 are separated.
  • the wafer length for 220 mm heads must be 230 mm.
  • the wafers 149 can also be supported by these tags 148 during the various chemical processing steps to prevent processing "shadows" from affecting the regions of the ZBJ chip 100.
  • the full width colour ZBJ chip 110 has dimensions of approximately 220 mm ⁇ 4 mm, yet requires very fine line widths, such as 3 microns for the one nozzle per pixel design, and 2 microns for the four nozzle per pixel design. The maintain focus and resolution when imaging the resist patterns is difficult, but is within the limits of current technology.
  • Either full wafer projection printing or an optical stepper can be used. In both cases, the projection equipment requires modification to the stage to allow for 220 mm travel in the long axis.
  • a scanning projection printer is modified to match the mask transport mechanism to permit very long masks. Defects caused by particles on the mask are projected at a 1:1 ratio and are in focus, so cleaner conditions are required to achieve the same defect level.
  • a 1:1 projection printer also requires a mask of an image area of 220 mm ⁇ 104 mm. This requires modification to the mask fabrication process. The manufacturing of 2 micron resolution masks of this size is viable for high volume production, but the masks are very expensive in small volumes. For these reasons, a stepper configuration should also be considered.
  • 5:1 reduction stepper reduces some of the problems associated with a scanning projection printer, particularly those associated with the production of very large masks, and the particle contamination of the mask.
  • some new problems are introduced. Firstly, a different imaging area of 10 mm ⁇ 8 mm is used. Then the full size wafer can be imaged in 22 ⁇ 13 steps. This provides a total of 286 steps which generally takes about 250 seconds to print. As there are approximately 10 imaging steps required for the manufacture of the ZBJ chip 100, total exposure time per wafer can be about 2,500 seconds which substantially reduces the production rate of such devices. Also, the use of the wafer stepper introduces the following two problems which effect the ZBJ chip design:
  • the first of these problems can be countered by using a repeating design, and ensuring that alignment at the perimeters of that repeating block is not critical.
  • the repeating block does not have to be rectangular, but can avoid critical features such as nozzles.
  • the left hand and right hand edges of the mask pattern can be quite irregular, provided they match each other.
  • each signal line must terminate at the bonding pads 207,223, which are typically arranged at the side edges of the chip 100. This normally requires that the side edges of the chip 100 be imaged with a different pattern than that of the centre of the ZBJ chip 100. This can be achieved by blading the mask to obscure the bonding pads and associated circuitry on all but the first exposure of the chip.
  • Fig. 70 shows a basic floor plan or chip layout of a stepper mask for a full width continuous tone colour ZBJ chip 100, including complete redundancy for full fault tolerance.
  • the magnified portion of the drawing illustrates an irregular mask boundary 258.
  • the ZBJ chips 100 can be processed in a manner very similar to standard semiconductor processing. There are however, some extra processing steps required. These are: accurate wafer thickness control, deposition of a HfB2 heater element; etching of the nozzle tip; back etching of the ink channels; and back etching of the nozzle barrels.
  • NMOS process with two level metal is assumed as this is the basis of the four nozzle per pixel design.
  • CMOS or bipolar processes can also be used.
  • Wafer preparation for scanning BJ heads is similar to that for standard semiconductor devices, except that the back surface must also be accurately ground and polished, and wafer thickness maintained at better than 5 microns. This is because both sides of the wafer are photolithographically processed, and etch depth from the reverse side is critical.
  • Full width fixed ZBJ chips require different wafer preparation than do those used in scanning heads, as the ZBJ chip must be at least 210 mm long in order to be able to print an A4 page, and at least 297 mm long for a A3 pages. This is much wider than the typical silicon crystalline cylinder. Wafers can be sliced longitudinally from the cylinder to accommodate the long chips required.
  • the resultant wafer When the wafer has been ground and polished the resultant wafer should generally be about 600 microns thick.
  • the resultant wafer is a rectangular shape approximately 230 mm ⁇ 104 mm ⁇ 600 microns thick. On this wafer, approximately 25 full colour heads can be processed. Such a wafer will appear similar to that of Fig. 69.
  • a 230 mm long 6 inch cylinder can be used to produce up to 2,600 full width, full colour heads before yield losses.
  • wafer flatness requirements are no more severe than those of the transistor fabrication processes.
  • the wafer can be gettered using back-side phosphorous diffusion, but back-side damage can result and therefore is not recommended because the back-side is subsequently etched.
  • Wafer processing of the ZBJ chip 100 uses a combination of special processes required for heater deposition and nozzle formations, and standard processes used for drive electronics fabrication. As the size of the ZBJ chip 100 is largely determined by the nozzles 110 and not by the drive transistors 164,193, there is little size advantage in using a very fine process.
  • the process disclosed here is based on a 2 micron self-aligned polysilicon gate NMOS process, but other processes such as CMOS or bipolar can be used.
  • the process size disclosed here is the largest size compatible with the interconnect density required to the nozzles 113 of the high density four colour ZBJ head. This also requires two levels of metal. Two levels of metal can be required for simpler heads, as high current tracks run across the chip, and very long clock tracks run along the chip.
  • the wafer processing stops required for the formation of the ZBJ nozzles 110 are intermingled with the steps required for the drive transistors.
  • the process used for the drive transistors can be standard as known to those skilled in the art, there is no requirement to specify such steps in this specification.
  • Figs. 71 to 80 show the cross section for a single nozzle corresponding to the cross-sectional lines shown in Fig. 12.
  • Figs. 71 to 80 also illustrate the corresponding and simultaneous construction of transistors arranged outboard of the nozzle arrays.
  • a 0.5 micron layer 132 of thermal SiO2 is grown on the P-type doped substrate 130. This is patterned with the driver circuit requirements as well as with the thermal shunt vias 400.
  • a thin gate oxide is thermally grown on the substrate 130. This will also affect the electrical connections of the thermal shunt 140 to the substrate 130, but will have an insignificant effect on thermal conduction.
  • Polysilicon is deposited to form the gates 403 and interconnects of the transistors. The drain and source of the transistors are N-type doped using the polysilicon gate 403 as a mask. This will also dope the thermal shunt connection 403 to the substrate 130.
  • a 0.05 micron layer of HfB2 is deposited to form the heater 120.
  • a 0.5 micron layer of aluminium is deposited over the substrate 130 to form the first level of metal 134.
  • a resist is patterned with the sum of the heater and the first level metal 134, and wet etched with a phosphoric acid-nitrate etchant.
  • the HfB2 layer is reactive ion etched using the aluminium as a mask.
  • the etch is performed with a halogenic gas such as CCl4 (carbon tetrachloride), as described in US Patent No. 4,889,587.
  • the wafer is then at the stage illustrated in Fig. 72.
  • the mask shows the ground common track 405 and the V+ common track 405.
  • a resist is then patterned with a pattern which exposes the heater element 120, and wet etched with a phosphoric acid-nitric etchant.
  • the wafer then corresponds to that illustrated in Fig. 73, also showing a heater connection electrode 407, and HfB2 408 under aluminium.
  • Fig. 74 illustrates the provision of the interlevel oxide 136. This is layer of CVD SiO2 or PECVD SiO2, approximately 1 micron thick. The thickness of this layer can be determined by the thermal lag required between the heater 120 and the thermal shunt 140.
  • Fig. 74 shows the cross-section of the water after this step in which 410 is a thermal shunt via, 411 represents the nozzle cavity, 412 a via for connection to the transistor and 413 the heater connection vias.
  • the second level metal 138 is formed as a layer of 0.5 micron aluminium which forms both the thermal shunt 140 and the second level of interconnects 144 to the heaters 120, heater connection 416 and connection 415 for the drive circuitry.
  • Two levels of metal are unlikely to be necessary for ZBJ heads with one nozzle per pixel, but are likely to be required for high speed colour heads with four nozzles per pixel.
  • the thickness and material of this layer can be changed to suit the thermal requirements of the heater chamber depending on the specific application.
  • a CVD glass overcoat 142 is applied, approximately 4 microns thick.
  • a low temperature CVD process such as PECVD, can be used. This layer is very thick and provides mechanical strength for the nozzle tip 417, as well as environmental protection.
  • a 17 micron diameter hole is RIE etched through the 4 micron glass overcoat with an SiO2 etching species. This forms the top of the nozzle tip 417 and completes the configuration illustrated in Fig. 76.
  • the hole (417) formed by a RIE of SiO2 is extended at least 30 microns into the silicon by further RIE, using a silicon etching gas.
  • the SiO2 overcoat is used as the RTE mask.
  • RIE is relatively unselective, a substantial amount of the SiO2 overcoat will be sacrificed.
  • the etch rate is 5:1 (Si:SiO2)
  • the CVD glass overcoat is deposited to a depth of 10 microns so that 4 microns remains after etching the silicon.
  • This hole (417) can be etched as deeply as possible to minimise accuracy requirements in the depth of back etching of the nozzle barrel (113). Reactive ion etching is used to obtain near vertical side walls, to ensure that the ink flows to the end of the nozzle by surface tension.
  • the wafer is back-etched to a thickness of approximately 200 microns.
  • the actual thickness is not critical, but the variation in thickness is, however.
  • the wafer must be etched such that the thickness variation is less than ⁇ 2 microns over the wafer. If this is not achieved, it is difficult to subsequently ensure that the process of back etching the nozzles does not over-etch and destroy the heaters.
  • the next step for a four colour head is to RIE etch ink channels 101 in the reverse side of the surface of the chip 100 in the manner illustrated in Figs. 6 to 9.
  • These channels 101 (Fig. 5) are approximately 600 microns wide ⁇ 100 microns deep.
  • These channels 101 are not essential to the operation of the ZBJ chip 100, but have two advantages. Namely, the channels 101 reduce the ink flow rate through the filter from approximately 8 mm per second to 2 mm per second. This flow rate reduction can alternatively be achieved by locating the filter differently in the ZBJ head 200. Also, the channels reduce the depth that the nozzles 110 need to be etched from 190 microns to 90 microns. As the nozzle barrels 113 are 40 microns in diameter, this has a major effect on the ratio of length to diameter of the barrels 113.
  • the ink channel back etch 420 has the disadvantage of weakening the wafer substantially. This step can be omitted if desired.
  • the ink channel back-etching process can also be used to thin the wafer along the dice lines in the manner earlier described with reference to Fig. 68.
  • the etch depth of the next step, nozzle barrel back- etching 419, is critical to ensure that the nozzle barrel 113 properly joins with the nozzle tip 417 (111) to form the thermal chamber.
  • a solution to this problem is to incorporate end point detection using optical spectroscopy.
  • a chemical etch stop signal can be created by filling the nozzle tips 417 previously etched from the front surface of the substrate with a detectable chemical signature, and monitoring the exhaust gases with an emission spectroscope.
  • the nozzle barrels 113 are formed with an anisotropic reactive ion etch of silicon. Holes 40 microns in diameter (later widened to 60 microns with an isotropic plasma etch), are etched 70 microns into the silicon from the reverse side of the wafer. These holes are at the bottom of the previously etched ink channels, which are 100 microns deep. As the wafer is thinned to 200 microns, these holes etch to within 30 microns of the front surface of the silicon.
  • etch can be stopped, even if some of the nozzles have not joined up to the tips. This is because the next step (10 micron isotropic etching of all exposed silicon) joins up any that are within about 12 microns.
  • Fig. 77 shows the ZBJ chip at the end of this step.
  • Etch depth uniformity over the entire wafer surface is critical. The tolerance depends largely upon the depth of each etch achievable with the 18 micron hole etched from the front of the chip. Given that the front etched hole is etched 30 ⁇ 2 microns, wafer thickness is 200 ⁇ 2 microns, ink channel back etch depth is 100 ⁇ 4 microns, overall isotropic etch of silicon is 10 ⁇ 1 microns, maximum joining distance is 12 microns, and the minimum between the nozzle barrel and the heater is 10 microns, cumulative tolerances mean that the nozzle barrel etch must be 70 ⁇ 4 microns. All of these tolerances can be loosened if the front etch can be deeper than 30 microns. The accuracy of alignment of the back-etching process to the front surface processes need only be to within ⁇ 10 microns, as alignment of the barrel and tip is not critical.
  • Fig. 78 The cumulative effect of these tolerances is illustrated in Fig. 78.
  • the cross-hatched area 424 seen in Fig. 78 shows the region of uncertainty in the final nozzle geometry, and the single-hatched area 423 shows the safety margin for the nozzle barrel to nozzle tip join using these tolerances. This safety margin is required because the reactive ion etches will not leave perfectly flat bottomed holes.
  • the uncertainty of the wafer thickness (200 ⁇ 2 microns) and the channel etch (100 ⁇ 4 microns) are combined into one thickness figure of 100 ⁇ 6 microns as the channels are too large to be shown in this figure.
  • the resist must be very thick to be maintained for 70 microns of RIE; the etch is deep and narrow, giving problems with removal of spent etchant; shadowing of the projection pattern by the walls of the ink channels must be avoided; and adequate resist coverage of the stepped surface must be achieved. This is not critical as etching of the ink channel walls can be tolerated.
  • the entire ZBJ wafer is then subjected to a 10 ⁇ 1 micron isotropic plasma etch of all exposed silicon.
  • This has two purposes. Firstly, this forms the thermal chamber 115 by undercutting 425 the thermal silicon dioxide 132 in the region of the heater 120. This is also to ensure that the nozzle barrels 113 join with the nozzle tips 111 resulting from a widening 426 of the barrels 113. As the wafer is etched from both sides, any non-joining barrels 113 and tips 111 that are within 18 microns (twice (10-1) microns) should join up. Non-joining barrels and tips within approximately 12 microns will behave essentially similarly to joined barrels and tips. This reduces the accuracy requirements of the barrel back-etch 419.
  • the etch must be highly selective towards silicon, and have a negligible etch rate with thermal silicon dioxide, otherwise the heater insulation layer 132 will be destroyed. This results in the configuration illustrated in Fig. 79.
  • the 4 micron glass overcoat 142 must now be etched to expose the bonding pads. This is not performed before the nozzle tip silicon etch because poor selectivity can cause the 30 micron RIE silicon etch to etch through the aluminium layer 139.
  • the ZBJ chip 100 can then be passivated with a 0.5 micron layer 144 of tantalum or other suitable material. It can be difficult to achieve a highly conformal coating, but irregularities in the passivation thickness will not substantially affect the performance of the ZBJ chip 100.
  • the ZBJ chip 100 has no electrical output, and therefore true functional testing can only be achieved by loading the device with ink into printing and printing patterns which exercise each individual nozzle 110. This cannot be performed at multi-probe time.
  • An effective method of functional testing the chips 100 at multi-probe time is to test the power consumption in the V+ to ground path as each heater 120 is turned on in sequence. Each time a heater 120 is fired, a current pulse should occur. As this is a separate circuit with negligible quiescent current, these pulses are readily detected.
  • the entire pattern of operational heaters and redundant circuits can be determined in approximately 1 second with inexpensive equipment. Therefore the entire wafer can be multi-probed in under one minute.
  • the pattern of functional and non-functional heaters can be read into a computer and used for compiling process statistics and detecting local quality control problems.
  • Scribing is along the top surface at the etched dice channels 147 (see Fig. 68).
  • the end tabs 148 for handling must be diced off before the ZBJ chips 100 can be separated.
  • the chips 100 can be glued in place in the head assemblies 200 and connected using tape automated bonding, with one tape along each edge of the chip. Alternatively, standard wire bonding can be used, as long as enough wires are bonded to meet the high current requirements of the chip 100.
  • Fig. 80 illustrates the cross-section of the completed device.
  • Fig. 82 is a plan view of typical components used in a ZBJ chip of the structure shown in Fig. 18.
  • Figs. 83 to 113 are vertical cross-sections through the centre line of Fig. 82 at various manufacturing stages.
  • Fig. 83 The manufacturing process commences with a standard silicon wafer of P-type doping with a resistivity of approximately 25 ohm cm.
  • Fig. 84 A layer of silicon nitride 501 approximately 0.15 microns thick is grown on the wafer 500. This is a standard NMOS process .
  • a first mask 501 is used to pattern the silicon nitride 501 to prepare for boron implantation.
  • Fig. 86 The wafer 500 is implanted with a field 503 of boron to eliminate the formation of spurious transistors.
  • Fig. 87 A thermal oxide layer 504 approximately 0.8 microns thick is grown on the boron implanted field 503.
  • Fig. 88 The remaining silicon nitride 501 is removed.
  • Fig. 89 This is a standard NMOS process which implants arsenic to form regions 505 for deletion mode transistors. This step involves the spin deposition of a resist, exposure of the resist to the second mask, development of the resist, arsenic implantation, and resist removal.
  • Fig. 90 A 0.1 micron gate oxide 506 is thermally grown. This is part of a standard NMOS process and increases the field oxide thickness to 0.9 microns.
  • Fig. 91 A 1 micron layer of polysilicon 507 is deposited over the entire wafer 500 using chemical vapour deposition.
  • Fig. 92 The polysilicon 507 is patterned using a third mask 508.
  • the wafer 500 is spin coated with resist.
  • the resist is exposed using the third mask and developed.
  • the polysilicon 507 is then etched using an anisotropic ion enhanced etching to reduce undercutting.
  • Fig. 93 The gate oxide 506 is etched where exposed by the polysilicon etch of the third mask. This results in etch diffusion windows 509 being formed and will also thin the field oxide 504 leaving a thickness of 0.8 microns.
  • Fig. 94 N+ diffusion regions 510 approximately 1 micron deep are formed in the diffusion windows 509.
  • Fig. 95 A 1 micron layer of glass 511 is deposited using chemical vapour deposition.
  • Fig. 96 The CVD glass 511 is etched where contacts are required to the polysilicon 507, the diffusions 510 and in the heater region. Contact regions 512 are formed. This process differs from the standard NMOS process in that the depth of etch is controlled so that there is an appropriate amount of thermal SiO2 504 remaining under the heaters.
  • Fig. 97 A 0.05 micron layer 513 of HfB2 is deposited over the wafer 500. This is not a standard NMOS process.
  • Fig. 98 A HfB2 layer 513 is etched using ion enhanced etching with CCl4 as the etchant. This exposes the heaters 514. This step requires spin coating of resist, exposure to a fifth level mask, development at resist, ion enhanced etching, and resist stripping.
  • Fig. 99 A 1 micron first metal level 515 of aluminium is evaporated over the wafer 500.
  • Fig. 100 The first metal level 515 is etched using a sixth level mask. This step requires spin coating of resist, exposure to the sixth mask, development of resist, plasma etching, and resist stripping. The etch must be strongly selective over HfB2, as the HfB2 layer is only 0.05 microns and will be exposed when the metal 515 is etched.
  • Fig. 101 A 1 micron layers 516 of glass is deposited using chemical vapour deposition.
  • Fig. 102 Pattern contacts for the seventh level mask are made using a standard contact etch for 2 micron NMOS with double level metal. This step requires spin coating of resist, exposure to the seventh mask, development of resist, ion enhanced etching, and resist stripping.
  • Fig. 103 A 1 micron second level metal layer 517 of aluminium is evaporated over the wafer 500.
  • This metal layer 517 provides the second level of contacts. This is required because a high wiring density is required to the heaters 514, which must be metal for low resitance.
  • This layer also provides the thermal diffuser or thermal shunt as described in the earlier embodiments.
  • Fig. 104 The second level metal 517 is etched using an eighth mask. This step requires spin coating of resist, exposure to the eighth mask, development of the resist, plasma etching, and resist stripping. This is a normal NMOS step.
  • the isolated metal disk above the heaters 514 is the thermal diffuser used to distribute waste heat to avoid hot-spots.
  • Fig. 105 A thick layer 518 of glass is deposited over the wafer 500.
  • the layer 518 must be thick enough to provide adequate mechanical strength to resist the shock of imploding bubbles. Also, enough glass must be deposited to diffuse the heat over wide enough area so that the ink does not boil when in contact with it. 4 micron thickness is considered adequate, but can be easily varied if desired.
  • Fig. 106 This step requires etching using a ninth level mask of a cylindrical barrel 519 into the overcoat 518, through the thermal oxide layer 504 down to the implanted field 503. Both CVD glass and thermal quartz are etched. This step requires spin coating of resist, exposure to a ninth level mask, development of resist, and anisotropic ion enhanced etching, and resist stripping.
  • the thermal chamber 520 is formed by an isotropic plasma etch of silicon, highly selective over SiO2. This is essential, as otherwise the protective layer or SiO2 separating the heater 514 from the passivation will be etched.
  • the previously etched barrel 519 acts as the mask for this step. In this case, an isotropic etch of 17 microns is used. Care must be taken not to fully etch the thermal SiO2 layer 501.
  • Nozzle channels 521 are etched from the reverse side of the wafer 500 by an anisotropic ion enhanced etching.
  • the channels 521 are about 60 microns in diameter, and about 500 microns deep.
  • the depth of the channels 521 is such that the distance between the top of the channel and the bottom of the thermal chamber 520 is the required nozzle length.
  • the etching place through a layer of resist 522.
  • Fig. 109 The nozzle via is etched from the front side of the wafer 500 using a highly an anisotropic ion enhanced etching. This etch is from the bottom of the the thermal chamber 520 to the top of the back etched nozzle channels 521, and is about 20 microns in length, and 20 microns in diameter.
  • the nozzle barrels 523 are formed therefrom.
  • Fig. 110 A 0.5 micron passivation layer 524 of tantalum is conformably coated over the entire wafer 500.
  • Fig. 111 In this step, windows are opened for the bonding pads 525. This requires a resist, coating, exposure to a twelfth level mask, resist. development, etching of the tantalum passivation layer 524, ion enhance etching of the overcoat 518, and resist stripping. As 2 microns of aluminium is available in the pad regions, it is easy to avoid etching through the pads formed by the second level metal 517.
  • Fig. 112 After probing of the wafer 500, the ZBJ chip is mounted into a frame or support extrusion as earlier described and glued into place. Wires 526 are bonded to the pads formed by the second level metal 525 at the ends of the chip. Power rails are bonded along the two long edges of the chip. Connections are then potted in epoxy resin.
  • Fig. 113 This shows a forward ejection type ZBJ nozzle filled with ink 527. In this case, the droplet is ejected downwards when the nozzle fires.
  • This type of head requires priming of ink using positive pressure, as it will not be filled by capiliary action.
  • a similar head construction can be used for reverse firing nozzles by filling the head heat chip from the other side.
  • the ZBJ printhead 200 incorporating the ZBJ chip 100 is useful in a variety of printing applications either printing across the page in the traditional manner, as a scanning print head, or as a stationary full width print head.
  • Figs. 114 to 118 show various configurations for use of a number of ZBJ heads.
  • Fig. 114 shows a colour photocopier 531 which includes a scanner 541 for scanning a page to be copied.
  • the scanner 541 outputs red, green and blue (RGB) data to a signal processor 543 which converts the RGB data into dot screened cyan, magenta, yellow and black (CMYK) suitable for printing using the device 100.
  • the CYMK data is input to a data formatter 545 which acts in a manner of the circuitry depicted in Figs. 56 and 57.
  • the data formatter 545 outputs to a full colour ZBJ head 550 capable of printing at 400 pixels per inch across an A3 page carried by a paper transport mechanism 547.
  • a controlling microcomputer 549 co-ordinates the operation of the photocopier 531 through a sequencing control of the scanning 541, signal processor 543, and paper transport mechanism 547.
  • Fig. 115 shows a colour facsimile machine 533 which includes some components designated in a similar manner to that of Fig. 114.
  • the scanner 541 scans a page to be transmitted after which the scanned data of the image is compressed by a compressor 560.
  • the compressor 560 can use any standard data compression system for images such as the JPEG standard.
  • the compressor 560 outputs transmit data to a modem 562 which connects to a PSTN or ISDN network 564.
  • the modem 562 receives data and outputs to an image expander 566, complementary to the compressor 560.
  • the expander 566 outputs to the data formatter 545 in the manner described above. In this configuration a colour ZBJ head 551 of a size greater than the full width of the paper to be printed is used.
  • Fig. 116 shows a computer printer 535 which can print either colour or black and white images depending on the type of ZBJ head used.
  • Data is supplied via an input 569 to a data communications receiver 568.
  • a microcontroller 549 buffers received data to an image memory 571 which outputs to a full colour data formatter in the manner described above or a simple black and white data formatter.
  • the data formatter 545 outputs to a full length ZBJ head 552 for printing on paper carried by the paper transport mechanism 547.
  • a video printer 537 which accepts video data via an input 574 which is input to a television decoder and ADC unit 573 which outputs image pixel data to a frame store 575.
  • a signal processor 543 converts RGB data to CMYK data for printing in the manner previously described.
  • a small colour ZBJ head 553 prints on a photographed sized paper carried by the paper transport 547 for printing.
  • Fig. 118 shows the configuration of a simple printer 539 in which page formatting is performed in a host computer 577.
  • the computer 577 outputs data and control information to a buffer 579 which outputs to the data formatter 545 in the manner described above.
  • a simple control logic unit 581 also receives commands from the host computer 577 for control of the paper transport mechanism 547.
  • ZBJ heads can be used in any of the above embodiments.
  • multi-head redundancy as previously described can be used in both page printing and scanning heads.
  • ultra-high resolution (1600 dpi) monochrome printing can be used in any embodiment.
  • a bubblejet print device (100) which is integrally formed having arrays (102,103,104,105) of nozzles (110) which form part of a passageway communicating between opposite surfaces of a semiconductor substrate (130).
  • Each nozzle (110) has an integrally formed heater (120) which permits heating of ink (106) within the respective nozzle (110) for the ejection of an ink drop (108) therefrom.
  • the heater (120) can provide a fault tolerant structure through the provision of a main heater (121,441) and a redundant heater (122,443) each of which can be separately energised from a corresponding electronic drive circuit (160, 165).
  • a bubblejet print head (200) incorporating the device (100) can form part of an image reproducing apparatus (531,533,535,537) and is capable of printing full colour images at 400 dpi and monochrome images up to 1600 dpi.
  • An ink drop size of about 3 picolitres is used for these image intensities.
  • a thermal shunt (140) or diffuser (491) are used to transport heat away from the heater (120) to prevent formation of hot spots thereabout after the ejection of an ink drop (108).
  • Electronic circuitry (310,302-305) is disclosed which is used to couple data to the device (100) to provide full width page printing using a stationary head (200) and a moving paper medium (220).

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • Geometry (AREA)
  • Particle Formation And Scattering Control In Inkjet Printers (AREA)
  • Ink Jet (AREA)
EP92101474A 1991-01-30 1992-01-29 Structures des éjecteurs pour imprimantes à jet d'encre Expired - Lifetime EP0498291B1 (fr)

Applications Claiming Priority (36)

Application Number Priority Date Filing Date Title
AUPK437491 1991-01-30
AU4374/91 1991-01-30
AU4735/91 1991-02-22
AU4746/91 1991-02-22
AUPK474691 1991-02-22
AUPK473291 1991-02-22
AUPK473591 1991-02-22
AU4743/91 1991-02-22
AU4738/91 1991-02-22
AU4733/91 1991-02-22
AUPK473691 1991-02-22
AUPK473791 1991-02-22
AUPK473191 1991-02-22
AUPK474391 1991-02-22
AUPK474191 1991-02-22
AU4734/91 1991-02-22
AUPK474591 1991-02-22
AU4731/91 1991-02-22
AU4741/91 1991-02-22
AU4744/91 1991-02-22
AU4745/91 1991-02-22
AU4740/91 1991-02-22
AUPK474091 1991-02-22
AU4732/91 1991-02-22
AU4736/91 1991-02-22
AU4739/91 1991-02-22
AU4742/91 1991-02-22
AUPK473491 1991-02-22
AUPK473891 1991-02-22
AU4737/91 1991-02-22
AUPK473991 1991-02-22
AUPK474291 1991-02-22
AUPK474491 1991-02-22
AUPK473391 1991-02-22
AU89996/91 1991-12-23
AU89996/91A AU657930B2 (en) 1991-01-30 1991-12-23 Nozzle structures for bubblejet print devices

Publications (2)

Publication Number Publication Date
EP0498291A1 true EP0498291A1 (fr) 1992-08-12
EP0498291B1 EP0498291B1 (fr) 1996-04-10

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Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2691403A1 (fr) * 1992-04-28 1993-11-26 Inkjet Systems Gmbh Co Kg Tête d'impression à encre électrothermique à plusieurs couches.
GB2267255A (en) * 1992-04-28 1993-12-01 Inkjet Systems Gmbh Co Kg ink-throttling arrangements in an ink-jet printer.
WO1996032695A1 (fr) * 1995-04-12 1996-10-17 Eastman Kodak Company Tolerance de defauts integree dans des mecanismes d'impression
WO1996032280A1 (fr) * 1995-04-12 1996-10-17 Eastman Kodak Company Connexion d'alimentation pour tetes d'impression monolithiques
WO1996032259A2 (fr) * 1995-04-12 1996-10-17 Eastman Kodak Company Tolerance aux defaillances dans des imprimantes d'un grand volume
WO1996032281A2 (fr) * 1995-04-12 1996-10-17 Eastman Kodak Company Placement des buses dans les tetes monolithiques d'impression fonctionnant en goutte-a-la-demande
US5796416A (en) * 1995-04-12 1998-08-18 Eastman Kodak Company Nozzle placement in monolithic drop-on-demand print heads
US5808631A (en) * 1995-04-12 1998-09-15 Eastman Kodak Company Integrated fault tolerance in printing mechanisms
US5812162A (en) * 1995-04-12 1998-09-22 Eastman Kodak Company Power supply connection for monolithic print heads
US6030072A (en) * 1995-04-12 2000-02-29 Eastman Kodak Company Fault tolerance in high volume printing presses
EP1188475A3 (fr) * 2000-09-19 2003-07-23 Canon Kabushiki Kaisha Procédé pour la fabrication d'un support d'échantillon et dispositif utilisé dans le procédé
EP1413437A1 (fr) * 2002-10-25 2004-04-28 Eastman Kodak Company Dispositif de formation de gouttelettes d'encre et procédé pour utilisation dans système d'impression à jet d'encre
US6863375B2 (en) * 1997-05-14 2005-03-08 Seiko Epson Corporation Ejection device and inkjet head with silicon nozzle plate
GB2406309A (en) * 2001-09-29 2005-03-30 Hewlett Packard Co Fluid ejection device with drive circuitry proximate to heating element

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6209203B1 (en) 1998-01-08 2001-04-03 Lexmark International, Inc. Method for making nozzle array for printhead

Citations (2)

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Publication number Priority date Publication date Assignee Title
EP0244214A1 (fr) * 1986-04-28 1987-11-04 Hewlett-Packard Company Tête d'impression à jet d'encre thermique
EP0321075A2 (fr) * 1987-12-17 1989-06-21 Hewlett-Packard Company Tête d'imprimante à jet d'encre intégrée et son procédé de fabrication

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0244214A1 (fr) * 1986-04-28 1987-11-04 Hewlett-Packard Company Tête d'impression à jet d'encre thermique
EP0321075A2 (fr) * 1987-12-17 1989-06-21 Hewlett-Packard Company Tête d'imprimante à jet d'encre intégrée et son procédé de fabrication

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 12, no. 466 (M-772)7 December 1988 & JP-A-63 191 644 ( SEIKO EPSON CORPORATION ) 9 August 1988 *

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2691403A1 (fr) * 1992-04-28 1993-11-26 Inkjet Systems Gmbh Co Kg Tête d'impression à encre électrothermique à plusieurs couches.
GB2267255A (en) * 1992-04-28 1993-12-01 Inkjet Systems Gmbh Co Kg ink-throttling arrangements in an ink-jet printer.
GB2267254A (en) * 1992-04-28 1993-12-01 Inkjet Systems Gmbh Co Kg Structure of single-integrated-chip ink-jet print head.
GB2267255B (en) * 1992-04-28 1995-11-22 Inkjet Systems Gmbh Co Kg Improvements in and relating to electrothermal ink jet print heads
GB2267254B (en) * 1992-04-28 1996-03-20 Inkjet Systems Gmbh Co Kg Electrothermal ink jet print head
WO1996032281A3 (fr) * 1995-04-12 1996-11-14 Eastman Kodak Co Placement des buses dans les tetes monolithiques d'impression fonctionnant en goutte-a-la-demande
US6030072A (en) * 1995-04-12 2000-02-29 Eastman Kodak Company Fault tolerance in high volume printing presses
WO1996032259A2 (fr) * 1995-04-12 1996-10-17 Eastman Kodak Company Tolerance aux defaillances dans des imprimantes d'un grand volume
WO1996032281A2 (fr) * 1995-04-12 1996-10-17 Eastman Kodak Company Placement des buses dans les tetes monolithiques d'impression fonctionnant en goutte-a-la-demande
WO1996032259A3 (fr) * 1995-04-12 1996-11-14 Eastman Kodak Co Tolerance aux defaillances dans des imprimantes d'un grand volume
WO1996032695A1 (fr) * 1995-04-12 1996-10-17 Eastman Kodak Company Tolerance de defauts integree dans des mecanismes d'impression
US5796416A (en) * 1995-04-12 1998-08-18 Eastman Kodak Company Nozzle placement in monolithic drop-on-demand print heads
US5808631A (en) * 1995-04-12 1998-09-15 Eastman Kodak Company Integrated fault tolerance in printing mechanisms
US5812162A (en) * 1995-04-12 1998-09-22 Eastman Kodak Company Power supply connection for monolithic print heads
WO1996032280A1 (fr) * 1995-04-12 1996-10-17 Eastman Kodak Company Connexion d'alimentation pour tetes d'impression monolithiques
US6863375B2 (en) * 1997-05-14 2005-03-08 Seiko Epson Corporation Ejection device and inkjet head with silicon nozzle plate
EP1188475A3 (fr) * 2000-09-19 2003-07-23 Canon Kabushiki Kaisha Procédé pour la fabrication d'un support d'échantillon et dispositif utilisé dans le procédé
US7731904B2 (en) 2000-09-19 2010-06-08 Canon Kabushiki Kaisha Method for making probe support and apparatus used for the method
US9248445B2 (en) 2000-09-19 2016-02-02 Canon Kabushiki Kaisha Method for making probe support and apparatus used for the method
GB2406309A (en) * 2001-09-29 2005-03-30 Hewlett Packard Co Fluid ejection device with drive circuitry proximate to heating element
GB2406309B (en) * 2001-09-29 2006-02-08 Hewlett Packard Co Fluid ejection device with drive circuitry proximate to heating element
EP1413437A1 (fr) * 2002-10-25 2004-04-28 Eastman Kodak Company Dispositif de formation de gouttelettes d'encre et procédé pour utilisation dans système d'impression à jet d'encre

Also Published As

Publication number Publication date
ATE136500T1 (de) 1996-04-15
EP0498291B1 (fr) 1996-04-10
DE69209684T2 (de) 1996-10-17
ATE144741T1 (de) 1996-11-15
DE69209684D1 (de) 1996-05-15

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