Field of Invention
[0001] The present invention relates to the field of ink jet printing systems.
Background of the Art
[0002] Many different types of printing have been invented, a large number of which are
presently in use. The known forms of print have a variety of methods for marking the
print media with a relevant marking media. Commonly used forms of printing include
offset printing, laser printing and copying devices, dot matrix type impact printers,
thermal paper printers, film recorders, thermal wax printers, dye sublimation printers
and ink jet printers both of the drop on demand and continuous flow type. Each type
of printer has its own advantages and problems when considering cost, speed, quality,
reliability, simplicity of construction and operation etc.
[0003] In recent years, the field of ink jet printing, wherein each individual pixel of
ink is derived from one or more ink nozzles has become increasingly popular primarily
due to its inexpensive and versatile nature.
[0004] Many different techniques of ink jet printing have been invented. For a survey of
the field, reference is made to an article by J Moore, "Non-Impact Printing: Introduction
and Historical Perspective", Output Hard Copy Devices, Editors R Dubeck and S Sherr,
pages 207 - 220 (1988).
[0005] Ink Jet printers themselves come in many different types. The utilisation of a continuous
stream ink in ink jet printing appears to date back to at least 1929 wherein US Patent
No. 1941001 by Hansell discloses a simple form of continuous stream electro-static
ink jet printing.
[0006] US Patent 3596275 by Sweet also discloses a process of a continuous ink jet printing
including the step wherein the ink jet stream is modulated by a high frequency electro-static
field so as to cause drop separation. This technique is still utilised by several
manufacturers including Elmjet and Scitex (see also US Patent No. 3373437 by Sweet
et al)
[0007] Piezo-electric ink jet printers are also one form of commonly utilised ink jet printing
device. Piezo-electric systems are disclosed by Kyser et. al. in US Patent No. 3946398
(1970) which utilises a diaphragm mode of operation, by Zolten in US Patent 3683212
(1970) which discloses a squeeze mode of operation of a piezo electric crystal, Stemme
in US Patent No. 3747120 (1972) discloses a bend mode of piezo-electric operation,
Howkins in US Patent No. 4459601 discloses a Piezo electric push mode actuation of
the ink jet stream and Fischbeck in US 4584590 which discloses a sheer mode type of
piezo-electric transducer element.
[0008] Recently, thermal ink jet printing has become an extremely popular form of ink jet
printing. The ink jet printing techniques include those disclosed by Endo et al in
GB 2007162 (1979) and Vaught et al in US Patent 4490728. Both the aforementioned references
disclosed ink jet printing techniques rely upon the activation of an electrothermal
actuator which results in the creation of a bubble in a constricted space, such as
a nozzle, which thereby causes the ejection of ink from an aperture connected to the
confined space onto a relevant print media. Printing devices utilising the electro-thermal
actuator are manufactured by manufacturers such as Canon and Hewlett Packard.
[0009] As can be seen from the foregoing, many different types of printing technologies
are available. Ideally, a printing technology should have a number of desirable attributes.
These include inexpensive construction and operation, high speed operation, safe and
continuous long term operation etc. Each technology may have its own advantages and
disadvantages in the areas of cost, speed, quality, reliability, power usage, simplicity
of construction operation, durability and consumables.
[0010] Many ink jet printing mechanisms are known. Unfortunately, in mass production techniques,
the production of ink jet heads is quite difficult. For example, often, the orifice
or nozzle plate is constructed separately from the ink supply and ink ejection mechanism
and bonded to the mechanism at a later stage (Hewlett-Packard Journal, Vol. 36 no
5, pp33-37 (1985)). These separate material processing steps required in handling
such precision devices often adds a substantially expense in manufacturing.
[0011] Additionally, side shooting ink jet technologies (U.S. Patent No. 4,899,181) are
often used but again, this limit the amount of mass production throughput given any
particular capital investment.
[0012] Additionally, more esoteric techniques are also often utilised. These can include
electroforming of nickel stage (Hewlett-Packard Journal Vol. 36 no 5, pp33-37 (1985)),
electro-discharge machining, laser ablation (U.S. Patent No. 5,208,604), micro-punching,
etc.
[0013] The utilisation of the above techniques is likely to add substantial expense to the
mass production of ink jet print heads and therefore add substantially to their final
cost.
[0014] It would therefore be desirable if an efficient system for the mass production of
ink jet print heads could be developed.
[0015] Further, during the construction of micro electromechanical systems, it is common
to utilize a sacrificial material to build up a mechanical system, within the sacrificial
material being subsequently etched away so as to release the required mechanical structure.
For example, a suitable common sacrificial material includes silicon dioxide which
can be etched away in hydrofluoric acid. MEMS devices are often constructed on silicon
wafers having integral electronics such as, for example, using a multi-level metal
CMOS layer. Unfortunately, the CMOS process includes the construction of multiple
layers which may include the utilization of materials which can be attacked by the
sacrificial etchant. This often necessitates the construction of passivation layers
using extra processing steps so as to protect other layers from possible unwanted
attack by a sacrificial etchant.
[0016] In micro-electro mechanical system, it is often necessary to provide for the movement
of objects. In particular, it is often necessary to pivot objects in addition to providing
for fulcrum arrangements where a first movement of one end of the fulcrum is translated
into a corresponding measurement of a second end of the fulcrum. Obviously, such arrangements
are often fundamental to mechanical apparatuses.
[0017] Further, When constructing large integrated circuits or micro-electro mechanical
systems, it is often necessary to interconnect a large number of wire to the final
integrated circuit device. To this end, normally, a large number of bond pads are
provided on the surface of a chip for the attachment of wires thereto. With the utilization
of bond pads normally certain minimal spacings are utilized in accordance with the
design technologies utilised. Where are large number of interconnects are required,
an excessive amount of on chip real estate is required for providing bond pads. It
is therefore desirable to minimize the amount of real estate provided for bond pads
whilst ensuring the highest degree of accuracy of registration for automated attachment
of interconnects such as a tape automated bonding (TAB) to the surface of a device.
WO9712689 is an example of a fluid drop ejector and
discloses one wall comprising a thin elastic membrane having an orifice
defining a nozzle and means responsive to electrical signals for deflecting the membrane
to eject drops of fluid from said nozzle.
Summary of the invention
[0018] Accordingly the invention provides an ink jet nozzle arrangement according to claim
1. Advantageous embodiments are provided in the dependent claims. The invention also
provides a printhead according to claim 16.
Brief Description of the Drawings
[0019] Notwithstanding any other forms which may fall within the scope of the present invention,
preferred forms of the invention will now be described, by way of example only, with
reference to the accompanying drawings in which:
Fig. 638 to Fig. 640 are schematic sectional views illustrating the operational principles
of an embodiment;
Fig. 641(a) and Fig. 641(b) are again schematic sections illustrating the operational
principles of the thermal actuator device;
Fig. 642 is a side perspective view, partly in section of a single nozzle arrangement
constructed in accordance with an embodiments;
Fig. 643 to Fig. 650 side perspective views partly in section illustrating the manufacturing
steps of an embodiments; and
Fig. 651 illustrates an array of ink jet nozzles formed in accordance with the manufacturing
procedures of an embodiment.
Fig. 652 provides a legend of the materials indicated in Fig. 653 to Fig. 660;
Fig. 653 to Fig. 660 illustrate sectional views of the manufacturing steps in one
form of construction of an ink jet printhead nozzle arrangement;
Fig. 661 to Fig. 663 are schematic sectional views illustrating the operational principles
of an embodiment;
Fig. 664(a) and Fig. 664(b) illustrate the operational principles of the thermal actuator
of an embodiment;
Fig. 665 is a side perspective view of a single nozzle arrangement of an embodiment;
Fig. 666 illustrates an array view of a portion of a print head constructed in accordance
with the principles of an embodiment.
Fig. 667 provides a legend of the materials indicated in Fig. 668 to Fig. 676; and
Fig. 668 to Fig. 677 illustrate sectional views of the manufacturing steps in one
form of construction of an ink jet printhead nozzle.
Fig. 678 is a perspective view of an arrangement of four single thermal actuators
constructed in accordance with a further embodiment.
Fig. 679 is a close-up perspective view, partly in section, of a single thermal actuator
constructed in accordance with a further embodiment.
Fig. 680 is a perspective view of a single thermal actuator constructed in accordance
with a further embodiment, illustrating the thermal actuator being moved up and to
a side.
Fig. 681 is an exploded perspective view illustrating the construction of a single
thermal actuator in
A Description of IJ43 T
[0020] In an embodiment, ink is ejected out of a nozzle chamber via an ink ejection hole
as the result of the utilisation of a series of radially placed thermal actuator devices
that are arranged around the ink ejection nozzle and are activated so as to compress
the ink within the nozzle chamber thereby causing ink ejection.
[0021] Turning now to Fig. 638 to Fig. 640, there will first be illustrated the basic operational
principles of an embodiment. Fig. 638 illustrates a single nozzle chamber arrangement
4401 when it is in its quiescent state. The arrangement 4401 includes a nozzle chamber
4402 which is normally filled with ink so as to form a meniscus 4403 around an ink
ejection nozzle 4404. The nozzle chamber 4402 is formed within a wafer 4405. The nozzle
chamber 4402 supplied from an ink supply channel 4406 which can be etched through
the wafer 4405 through the utilisation of a highly isotropic plasma etching system.
A suitable etcher can be the Advance Silicon Etch (ASE) system available from Surface
Technology Systems of the United Kingdom.
[0022] The top of the nozzle chamber arrangement 4401 includes a series of radially placed
thermoactuator devices e.g. 4408, 4409. These devices comprise polytetrafluoroethylene
(PTFE) layer actuators having an internal serpentine copper core. Upon heating of
the copper core, the surrounding PTFE expands rapidly resulting in a generally downward
movement of the actuator 4408, 4409. Hence, when it is desired to eject ink from the
ink ejection nozzle 4404, a current is passed through the actuators 4408, 4409 which
results in them generally rapidly bending downwards as illustrated in Fig. 639. The
downward bending movement of actuators 4408, 4409 results in a substantial increase
in pressure within the nozzle chamber 4402. The rapid increase in pressure in nozzle
chamber 4402, in turn results in a rapid expansion of the meniscus 4403 as illustrated
in Fig. 639.
[0023] The actuators are turned on for a limited time only and subsequently deactivated.
A short time later the situation is as illustrated in Fig. 640 with the actuators
4408, 4409 rapidly returning to their original positions. This results in a general
inflow of ink back into the nozzle chamber and a necking and breaking of the meniscus
4403 resulting in the ejection of a drop 4412. The necking and breaking of the meniscus
is a consequence of the forward momentum of the ink associated with drop 4412 and
the backward pressure experienced as a result of the return of the actuators 4408,
4409 to their original positions. The return of the actuator also results in a general
inflow of ink 4406 from the supply channel as a result of surface tension effects
and, eventually, the state returns to the quiescent position as illustrated in Fig.
638.
[0024] Fig. 641(a) and Fig. 641(b) illustrate the principle of operation of the thermal
actuator. The thermal actuator is preferably constructed from a material 4414 having
a high coefficient of thermal expansion. Embedded within the material 4414 is a series
of heater elements e.g. 4415 which can be a series of conductive elements designed
to carry a current. The conductive elements 4415 are heated by means of passing a
current through the elements with the heating resulting in a general increase in temperature
in the area around the heating elements. The increase in temperature causes a corresponding
expansion of the PTFE which has a high coefficient of thermal expansion. Hence, as
illustrated in Fig. 641(b), the PTFE is bent generally in a down direction.
[0025] Turning now to Fig. 642, there is illustrated a side perspective view of one nozzle
arrangement constructed in accordance with the principles previously outlined. The
nozzle chamber 4402 can be constructed by means of an isotropic surface etch of the
wafer surface 4405. The wafer surface 4405 can include a CMOS layer including all
the required power and drive circuits. Further, a series of leaf or petal type actuators
e.g. 4408, 4409 are provided each having an internal copper core e.g. 4417 which winds
in a serpentine nature so as to provide for substantially unhindered expansion of
the actuator device. The operation of the actuator is similar to that as illustrated
in Fig. 641 (a) and Fig. 641(b) such that, upon activation, the petals e.g. 4408 bend
down as previously described. The ink supply channel 4406 can be created via a deep
silicon back edge of the wafer utilising a plasma etcher or the like. The copper or
aluminium coil e.g. 4417 can provide a complete circuit around each petal. A central
arm 4418 which can include both metal and PTFE portions provides the main structural
support for the petal arrangement in addition to providing a current trace for the
conductive heaters.
[0026] Turning now to Fig. 643 to Fig. 650, there will now be explained one form of manufacturing
of a printhead device operational in accordance with the principles of an embodiment.
The device is preferably constructed utilising microelectromechanical (MEMS) techniques
and can include the following construction techniques:
[0027] As shown initially in Fig. 643, the initial processing starting material is a standard
semi-conductor wafer 4420 have a complete CMOS level 4421 to the first level metal
step. The first level metal includes portions eg. 4422 which are utilized for providing
power to the thermal actuator.
[0028] The first step, as illustrated in Fig. 644, is to etch a nozzle region down to the
silicon wafer 4420 utilizing an appropriate mast
[0029] Next, as illustrated in Fig. 645, a 2 micron layer of polytetrafluoroethylene (PTFE)
is deposited and etched so as to include vias eg. 4424 for interconnecting multiple
levels.
[0030] Next, as illustrated in Fig. 646, the second level metal layer is deposited, masked
and etched so as to form heater structure 4425. The heater structure 4425 including
via interconnect 4426 with the lower aluminium layer.
[0031] Next, as illustrated in Fig. 647, a further 2µm layer of PTFE is deposited and etched
to the depth of 1µm utilizing a nozzle rim mask so as to form nozzle rim eg. 4428
in addition to ink flow guide rails eg. 4429 which generally restrain any wicking
along the surface of the PTFE layer. The guide rails eg. 4429 surround small thin
slots and, as such, surface tension effects are a lot higher around these slots which
in turn results in minimal outflow of ink during operation.
[0032] Next, as illustrated in Fig. 648, the PTFE is etched utilizing a nozzle and paddle
mask so as to define nozzle portion 4430 and slots eg. 4431 and 4432.
[0033] Next, as illustrated in Fig. 649, the wafer is crystal calligraphically etched on
the < 111 > plane utilizing a standard crystallographic etchant such as KOH. The etching
forms chamber 4432, directly below the ink ejection nozzle.
[0034] Next, turning to Fig. 650, the ink supply channel 4434 can be etched from the back
of the wafer utilizing a highly anisotropic etcher such as the STS etcher from Silicon
Technology Systems of United Kingdom.
[0035] Obviously, an array of ink jet nozzles can be formed simultaneously with a portion
of an array 4436 being illustrated in Fig. 651 with a portion of the printhead being
formed simultaneously and diced by the ST etch etching process. The array 4436 shown
provides for four column printing with each separate column attached to a different
colour ink supply channel being supplied from the back of the wafer. The bond pads
4437 provide for electrical control of the ejection mechanism.
[0036] In this manner, large pagewidth printheads can be formulated so as to provide for
a drop on demand ink ejection mechanism.
[0037] One form of detailed manufacturing process which can be used to fabricate monolithic
ink jet print heads operating in accordance with the principles taught by the present
embodiment can proceed utilizing the following steps:
- 1. Using a double sided polished wafer, complete a 0.5 micron, one poly, 2 metal CMOS
process. This step is shown in Fig. 653. For clarity, these diagrams may not be to
scale, and may not represent a cross section though any single plane of the nozzle.
Fig. 652 is a key to representations of various materials in these manufacturing diagrams,
and those of other cross referenced ink jet configurations.
- 2. Etch the CMOS oxide layers down to silicon or second level metal using Mask 1.
This mask defines the nozzle cavity and the edge of the chips. This step is shown
in Fig. 653.
- 3. Deposit a thin layer (not shown) of a hydrophilic polymer, and treat the surface
of this polymer for PTFE adherence.
- 4. Deposit 1.5 microns of polytetrafluoroethylene (PTFE).
- 5. Etch the PTFE and CMOS oxide layers to second level metal using Mask 2. This mask
defines the contact vias for the heater electrodes. This step is shown in Fig. 654.
- 6. Deposit and pattern 0.5 microns of gold using a lift-off process using Mask 3.
This mask defines the heater pattern. This step is shown in Fig. 655.
- 7. Deposit 1.5 microns of PTFE.
- 8. Etch 1 micron of PTFE using Mask 4. This mask defines the nozzle rim and the rim
at the edge of the nozzle chamber. This step is shown in Fig. 656.
- 9. Etch both layers of PTFE and the thin hydrophilic layer down to silicon using Mask
5. This mask defines the gap at the edges of the actuator petals, and the edge of
the chips. It also forms the mask for the subsequent crystallographic etch. This step
is shown in Fig. 657.
- 10. Crystallographically etch the exposed silicon using KOH. This etch stops on <111>
crystallographic planes, forming an inverted square pyramid with sidewall angles of
54.74 degrees. This step is shown in Fig. 658.
- 11. Back-etch through the silicon wafer (with, for example, an ASE Advanced Silicon
Etcher from Surface Technology Systems) using Mask 6. This mask defines the ink inlets
which are etched through the wafer. The wafer is also diced by this etch. This step
is shown in Fig. 659.
- 12. Mount the print heads in their packaging, which may be a molded plastic former
incorporating ink channels which supply the appropriate color ink to the ink inlets
at the back of the wafer.
- 13. Connect the print heads to their interconnect systems. For a low profile connection
with minimum disruption of airflow, TAB may be used. Wire bonding may also be used
if the printer is to be operated with sufficient clearance to the paper.
- 14. Fill the completed print heads with ink and test them. A filled nozzle is shown
in Fig. 660.
A Description of IJ44 T
[0038] An embodiment of the present invention discloses an inkjet printing device made up
of a series of nozzle arrangements. Each nozzle arrangement includes a thermal surface
actuator device which includes an L-shaped cross sectional profile and an air breathing
edge such that actuation of the paddle actuator results in a drop being ejected from
a nozzle utilizing a very low energy level.
[0039] Turning initially to Fig. 661 to Fig. 663, there will now be described the operational
principles of an embodiment. In Fig. 661, there is illustrated schematically a sectional
view of a single nozzle arrangement 4501 which includes an ink nozzle chamber 4502
containing an ink supply which is resupplied by means of an ink supply channel 4503.
A nozzle rim 4504 is provided, across which a meniscus 4505 forms, with a slight bulge
when in the quiescent state. A bend actuator device 4507 is formed on the top surface
of the nozzle chamber and includes a side arm 4508 which runs generally parallel to
the surface 4509 of the nozzle chamber wall so as to form an "air breathing slot"
4510 which assists in the low energy actuation of the bend actuator 4507. Ideally,
the front surface of the bend actuator 4507 is hydrophobic such that a meniscus 4512
forms between the bend actuator 4507 and the surface 4509 leaving an air pocket in
slot 4510.
[0040] When it is desired to eject a drop via the nozzle rim 4504, the bend actuator 4507
is actuated so as to rapidly bend down as illustrated in Fig. 662. The rapid downward
movement of the actuator 4507 results in a general increase in pressure of the ink
within the nozzle chamber 4502. This results in a outflow of ink around the nozzle
rim 4504 and a general bulging of the meniscus 4505. The meniscus 4512 undergoes a
low amount of movement.
[0041] The actuator device 4507 is then turned off so as to slowly return to its original
position as illustrated in Fig. 663. The return of the actuator 4507 to its original
position results in a reduction in the pressure within the nozzle chamber 4502 which
results in a general back flow of ink into the nozzle chamber 4502. The forward momentum
of the ink outside the nozzle chamber in addition to the back flow of ink 4515 results
in a general necking and breaking off of the drop 4514. Surface tension effects then
draw further ink into the nozzle chamber via ink supply channel 4503. Ink is drawn
in the nozzle chamber 4503 until the quiescent position of Fig. 661 is again achieved.
[0042] The actuator device 4507 can be a thermal actuator which is heated by means of passing
a current through a conductive core. Preferably, the thermal actuator is provided
with a conductive core encased in a material such as polytetrafluoroethylene which
has a high level coefficient of expansion. As illustrated in Fig. 664, the conductive
core 4523 is preferably of a serpentine form and encased within a material 4524 having
a high coefficient of thermal expansion. Hence, as illustrated in Fig. 664(b), on
heating of the conductive core 4523, the material 4524 expands to a greater extent
and is therefore caused to bend down in accordance with requirements.
[0043] Turning now to Fig. 665, there is illustrated a side perspective view, partly in
section, of a single nozzle arrangement when in the state as described with reference
to Fig. 662. The nozzle arrangement 4501 can be formed in practice on a semiconductor
wafer 4520 utilizing standard MEMS techniques.
[0044] The silicon wafer 4520 preferably is processed so as to include a CMOS layer 4521
which can include the relevant electrical circuitry required for the full control
of a series of nozzle arrangements 4501 formed so as to form a print head unit On
top of the CMOS layer 4521 is formed a glass layer 4522 and an actuator 4507 which
is driven by means of passing a current through a serpentine copper coil 4523 which
is encased in the upper portions of a polytetrafluoroethylene (PTFE) layer 4524. Upon
passing a current through the coil 4523, the coil 4523 is heated as is the PTFE layer
4524. PTFE has a very high coefficient of thermal expansion and hence expands rapidly.
The coil 4523 constructed in a serpentine nature is able to expand substantially with
the expansion of the PTFE layer 4524. The PTFE layer 4524 includes a lip portion 4508
which upon expansion, bends in a scooping motion as previously described. As a result
of the scooping motion, the meniscus 4505 generally bulges and results in a consequential
ejection of a drop of ink. The nozzle chamber 4504 is later replenished by means of
surface tension effects in drawing ink through an ink supply channel 4503 which is
etched through the wafer through the utilization of a highly an isotropic silicon
trench etcher. Hence, ink can be supplied to the back surface of the wafer and ejected
by means of actuation of the actuator 4507. The gap between the side arm 4508 and
chamber wall 4509 allows for a substantial breathing effect which results in a low
level of energy being required for drop ejection.
[0045] Obviously, a large number of arrangements 4501 of Fig. 665 can be formed together
on a wafer with the arrangements being collected into print heads which can be of
various sizes in accordance with requirements. Turning now to Fig. 666, there is illustrated
one form of an array 4530 which is designed so as to provide three colour printing
with each colour providing two spaced apart rows of nozzle arrangements 4534. The
three groupings can comprise groupings 4531, 4532 and 4533 with each grouping supplied
with a separate ink colour so as to provide for full colour printing capability. Additionally,
a series of bond pads e.g. 4536 are provided for TAB bonding control signals to the
print head 4530. Obviously, the arrangement 4530 of Fig. 666 illustrates only a portion
of a print head which can be of a length as determined by requirements.
[0046] One form of detailed manufacturing process which can be used to fabricate monolithic
ink jet print heads operating in accordance with the principles taught by the present
embodiment can proceed utilizing the following steps:
- 1. Using a double sided polished wafer, complete drive transistors, data distribution,
and timing circuits using a 0.5 micron, one poly, 2 metal CMOS process. Relevant features
of the wafer at this step are shown in Fig. 668. For clarity, these diagrams may not
be to scale, and may not represent a cross section though any single plane of the
nozzle. Fig. 667 is a key to representations of various materials in these manufacturing
diagrams, and those of other cross referenced ink jet configurations.
- 2. Etch the CMOS oxide layers down to silicon or second level metal using Mask 1.
This mask defines the nozzle cavity and the edge of the chips. Relevant features of
the wafer at this step are shown in Fig. 668.
- 3. Plasma etch the silicon to a depth of 20 microns using the oxide as a mask. This
step is shown in Fig. 669.
- 4. Deposit 23 microns of sacrificial material and planarize down to oxide using CMP.
This step is shown in Fig. 670.
- 5. Etch the sacrificial material to a depth of 15 microns using Mask 2. This mask
defines the vertical paddle at the end of the actuator. This step is shown in Fig.
671.
- 6. Deposit a thin layer (not shown) of a hydrophilic polymer, and treat the surface
of this polymer for PTFE adherence.
- 7. Deposit 1.5 microns of polytetrafluoroethylene (PTFE).
- 8. Etch the PTFE and CMOS oxide layers to second level metal using Mask 3. This mask
defines the contact vias for the heater electrodes. This step is shown in Fig. 672.
- 9. Deposit and pattern 0.5 microns of gold using a lift-off process using Mask 4.
This mask defines the heater pattern. This step is shown in Fig. 673.
- 10. Deposit 1.5 microns of PTFE.
- 11. Etch 1 micron of PTFE using Mask 5. This mask defines the nozzle rim and the rim
at the edge of the nozzle chamber. This step is shown in Fig. 674.
- 12. Etch both layers of PTFE and the thin hydrophilic layer down to the sacrificial
layer using Mask 6. This mask defines the gap at the edges of the actuator and paddle.
This step is shown in Fig. 675.
- 13. Back-etch through the silicon wafer to the sacrificial layer (with, for example,
an ASE Advanced Silicon Etcher from Surface Technology Systems) using Mask 7. This
mask defines the ink inlets which are etched through the wafer. This step is shown
in Fig. 676.
- 14. Etch the sacrificial layers. The wafer is also diced by this etch.
- 15. Mount the print heads in their packaging, which may be a molded plastic former
incorporating ink channels which supply the appropriate color ink to the ink inlets
at the back of the wafer.
- 16. Connect the print heads to their interconnect systems. For a low profile connection
with minimum disruption of airflow, TAB may be used. Wire bonding may also be used
if the printer is to be operated with sufficient clearance to the paper.
- 17. Fill the completed print heads with ink and test them. A filled nozzle is shown
in Fig. 677.
[0047] Of course other forms of thermal actuator construction could be used and there will
now be described one form of more complex thermal actuator construction of general
use in MEMS devices such as ink jet printers.
[0048] Turning to Fig. 678, there are illustrated 4 MEMS actuators 4520, 4521, 4522, 4523
as constructed in accordance with a further embodiment. In Fig. 679, there is illustrated
a close-up perspective view, partly in section, of a single thermal actuator constructed
in accordance with the further embodiment. Each actuator, e.g. 4520, is based around
three corrugated heat elements 4511, 4512 and 4513 which are interconnected 4514 to
a cooler common current carrying line 4516. The two heater elements 4511, 4512 are
formed on a bottom layer of the actuator 4520 with the heater element 4513 and common
line 4516 being formed on a top layer of the actuator 4520. Each of the elements 4511,
4512, 4513, 4514 and 4516 can be formed from copper via means of deposition utilising
semi-conductor fabrication techniques. The lines 4511, 4512, 4513, 4514 and 4516 are
"encased" inside a polytetrafluoroethylene (PTFE) layer, e.g. 4518 which has a high
coefficient of thermal expansion. The PTFE layer has a coefficient of thermal expansion
which is much greater than that of the corresponding copper layers 4512, 4513, 4514
and 4516. The heater elements 4511-4513 are therefore constructed in a serpentine
manner so as to allow the concertinaing of the heater elements upon heating and cooling
so as to allow for their expansion substantially with the expansion of the PTFE layer
4518. The common line 4516, also constructed from copper is provided with a series
of slots, e.g. 4519 which provide minimal concertinaing but allow the common layer
16 bend upwards and sideways when required.
[0049] Returning now to Fig. 678, the actuator, e.g. 4520, can be operated in a number of
different modes. In a first mode, the bottom two heater elements 4511 and 4512 (Fig.
679) are activated. This causes the bottom portion of the polytetrafluoroethylene
layer 4518 (Fig. 679) to expand rapidly while the top portion of the polytetrafluoroethylene
layer 4518 (Fig. 679) remains cool. The resultant forces are resolved by an upwards
bending of the actuator 4520 as illustrated in Fig. 678.
[0050] In a second operating mode, as illustrated in Fig. 678, the two heaters 4512, 4513
(Fig. 679) are activated causing an expansion of the PTFE layer 4518 (Fig. 679) on
one side while the other side remains cool. The resulting expansion provides for a
movement of the actuator 4520 to one side as illustrated in Fig. 678.
[0051] Finally, in Fig. 680, there is provided a further form of movement this time being
up and to a side. This form of movement is activated by heating each of the resistive
elements 4511-4513 (Fig. 679) which is resolved a movement of the actuator 4520 up
and to the side.
[0052] Hence, through the controlled use of the heater elements 4511-4513 (Fig. 679), the
position of the end point 4530 of the actuator 4520 (Fig. 678) can be fully controlled.
To this end the PTFE portion 4518 is extended beyond the copper interconnect 4514
so as to provide a generally useful end portion 4530 for movement of objects to the
like.
[0053] Turning to Fig. 681, there is illustrated an explosive perspective view of the construction
of a single actuator. The actuator can be constructed utilising semi-conductor fabrication
techniques and can be constructed on a wafer 4542 or other form of substrate. On top
of the wafer 4542 is initially fabricated a sacrificial etch layer to form an underside
portion utilising a mask shape of a actuator device. Next, a first layer of PTFE layer
4564 is deposited followed by the bottom level copper heater level 4545 forming the
bottom two heaters. On top of this layer is formed a PTFE layer having vias for the
interconnect 4514. Next, a second copper layer 4548 is provided for the top heater
and common line with interconnection 4514 to the bottom copper layer. On top of the
copper layer 4528 is provided a further polytetrafluoroethylene layer of layer 4544
with the depositing of polytetrafluoroethylene layer 4544 including the filling of
the gaps, e.g. 4549 in the return common line of the copper layer. The filling of
the gaps allows for a significant reduction in the possibilities of laminar separation
of the polytetrafluoroethylene layers from the copper layer.
[0054] The two copper layers also allow the routing of current drive lines to each actuator.
[0055] Hence, an array of actuators could be formed on a single wafer and activated together
so as to move an object placed near the array. Each actuator in the array can then
be utilised to provide a circular motion of its end tip. Initially, the actuator can
be in a rest position and then moved to a side position as illustrated for actuator
4520 in Fig. 678 then moved to an elevated side position as illustrated in Fig. 680
thereby engaging the object to be moved. The actuator can then be moved to nearly
an elevated position as shown for actuator 4520 in Fig. 678. This resulting in a corresponding
force being applied to the object to be moved. Subsequently, the actuator is returned
to its rest position and the cycle begins again. Utilising continuous cycles, an object
can be made to move in accordance with requirements. Additionally, the reverse cycle
can be utilised to move an object in the opposite direction.
[0056] Preferably, an array of actuators are utilised thereby forming the equivalent of
a cilia array of actuators. Multiple cilia arrays can then be formed on a single semi-conductor
wafer which is later diced into separate cilia arrays. Preferably, the actuators on
each cilia array are divided into groups with adjacent actuators being in different
groups. The cilia array can then be driven in four phases with one in four actuators
pushing the object to be moved in each portion of the phase cycle.
[0057] Ideally, the cilia arrays can then be utilised to move an object, for example to
move a card past an information sensing device in a controlled manner for reading
information stored on the card. In another example, the cilia arrays can be utilised
to move printing media past a printing head in an ink jet printing device. Further,
the cilia arrays can be utilised for manipulating means in the field of nano technology,
for example in atomic force microscopy (AFM).
[0058] Preferably, so as to increase the normally low coefficient of friction of PTFE, the
PTFE end 4520 is preferably treated by means of an ammonia plasma etch so as to increase
the coefficient of friction of the end portion.
[0059] It would be evident to those skilled in the art that other arrangements maybe possible
whilst still following in the scope of the present invention. For example, other materials
and arrangements could be utilised. For example, a helical arrangement could be provided
in place of the serpentine arrangement where a helical system is more suitable.
[0060] The presently disclosed ink jet printing technology is potentially suited to a wide
range of printing system including: colour and monochrome office printers, short run
digital printers, high speed digital printers, offset press supplemental printers,
low cost scanning printers high speed pagewidth printers, notebook computers with
inbuilt pagewidth printers, portable colour and monochrome printers, colour and monochrome
copiers, colour and monochrome facsimile machines, combined printer, facsimile and
copying machines, label printers, large format plotters, photograph copiers, printers
for digital photographic "minilabs", video printers, PhotoCD printers, portable printers
for PDAs, wallpaper printers, indoor sign printers, billboard printers, fabric printers,
camera printers and fault tolerant commercial printer arrays.
1. An ink jet nozzle arrangement comprising:
a nozzle chamber for storing ink to be ejected;
and characterized by:
at least one moveable actuator paddle forming at least a portion of a first wall of
said nozzle chamber; and
an ink ejection nozzle defined in said first wall,
wherein actuation of said at least one actuator paddle causes ejection of ink from
said nozzle.
2. An ink jet nozzle arrangement as claimed in claim 1 wherein said actuation causes
movement of said at least one actuator paddle inwards towards the centre of said nozzle
chamber.
3. An ink jet nozzle arrangement as claimed in claim 1 or 2, wherein said at least one
actuator paddle is actuated by means of a thermal actuator device.
4. An ink jet nozzle arrangement as claimed in any one of the preceding claims, wherein
said thermal actuator device comprises a conductive resistive heating element encased
within a second material having a high coefficient of thermal expansion.
5. An ink jet nozzle arrangement as claimed in any one of the preceding claims, wherein
said element is serpentine shaped to allow for substantially unhindered expansion
of said second material.
6. An ink ejection nozzle arrangement as claimed in any one of the preceding claims,
wherein said first wall comprises a nozzle rim and a plurality of actuator paddles
attached to the nozzle rim.
7. An ink ejection nozzle arrangement as claimed claim 6, wherein said actuator paddles
are actuated in unison so as to eject ink from said nozzle chamber via said ink ejection
nozzle.
8. An ink jet nozzle arrangement as claimed in claim 6, wherein said actuator paddles
are arranged radially around said nozzle rim.
9. An ink jet nozzle arrangement as claimed in any one of claims 6 to 8, wherein said
actuator paddles form a membrane between said nozzle chamber and an external atmosphere,
wherein said paddles bend away from said external atmosphere so as to cause an increase
in pressure within said nozzle chamber, thereby causing ejection of ink from said
nozzle chamber.
10. An ink jet nozzle arrangement as claimed in any one of the preceding claims, wherein
said arrangement is formed on a wafer utilizing micro-electro mechanical techniques,
said wafer further comprises an ink supply channel in fluid communication with said
nozzle chamber, said ink supply channel being etched through said wafer.
11. An inkjet nozzle arrangement as claimed in any one of claims 1 to 5, wherein one end
of said paddle actuator traverses along a second wall of said nozzle chamber during
ink ejection, said second wall being substantially perpendicular to said first wall.
12. An inkjet nozzle arrangement as claimed in claim 11, wherein said one end further
comprises a flange sealingly engaged with said second wall.
13. An ink jet nozzle arrangement as claimed in claim 12 further comprising an ink supply
channel interconnected to said nozzle chamber for the resupply of ink to said nozzle
chamber, said interconnection comprising a slot in a wall of said chamber, said slot
being substantially opposite an end of said flange.
14. An ink jet nozzle arrangement as claimed in claim 13 wherein said slot is arranged
in a corner of a third wall of said chamber and wherein said second wall of said chamber
further forms a wall of said ink supply channel.
15. An ink jet nozzle arrangement as claimed in claim 12 wherein said flange is configured
to constrict the flow of ink into said nozzle chamber during movement of said paddle
actuator.
16. An inkjet printhead comprising an inkjet nozzle arrangement as claimed in any one
of the preceding claims.
1. Tintenstrahldüsenanordnung, umfassend:
eine Düsenkammer zum Aufnehmen von auszustoßender Tinte;
und gekennzeichnet durch:
wenigstens ein bewegliches Aktuatorpaddel, das wenigstens einen Teilbereich einer
ersten Wand der Düsenkammer bildet; und
eine in der ersten Wand gebildete Tintenausstoßdüse,
wobei eine Stellbewegung des wenigstens einen Aktuatorpaddels ein Ausstoßen von Tinte
aus der Düse hervorruft.
2. Tintenstrahldüsenanordnung nach Anspruch 1, wobei die Stellbewegung eine Verschiebung
des wenigstens einen Aktuatorpaddels nach innen in Richtung zur Mitte der Düsenkammer
verursacht.
3. Tintenstrahldüsenanordnung nach Anspruch 1 oder 2, wobei das wenigstens eine Aktuatorpaddel
mittels einer thermischen Aktuatorbaugruppe betätigt wird.
4. Tintenstrahldüsenanordnung nach einem der vorhergehenden Ansprüche, wobei die thermische
Aktuatorbaugruppe ein leitfähiges Widerstandsheizelement umfasst, das in einem zweiten
Material mit einem hohen Wärmeausdehnungskoeffizienten eingeschlossen ist.
5. Tintenstrahldüsenanordnung nach einem der vorhergehenden Ansprüche, wobei das Element
mäanderförmig ausgebildet ist, um eine im Wesentlichen ungehinderte Ausdehnung des
zweiten Materials zu ermöglichen.
6. Tintenstrahldüsenanordnung nach einem der vorhergehenden Ansprüche, wobei die erste
Wand einen Düsenrand und mehrere am Düsenrand angebrachte Aktuatorpaddel umfasst.
7. Tintenstrahldüsenanordnung nach Anspruch 6, wobei die Aktuatorpaddel alle gemeinsam
betätigt werden, um Tinte aus der Düsenkammer über die Tintenausstoßdüse auszustoßen.
8. Tintenstrahldüsenanordnung nach Anspruch 6, wobei die Aktuatorpaddel radial um den
Düsenrand herum angeordnet sind.
9. Tintenstrahldüsenanordnung nach einem der Ansprüche 6 bis 8, wobei die Aktuatorpaddel
eine Membran zwischen der Düsenkammer und einer Außenatmosphäre bilden, wobei die
Paddel sich von der Außenatmosphäre weg nach innen biegen, um einen Druckanstieg in
der Düsenkammer zu verursachen, wodurch ein Ausstoßen von Tinte aus der Düsenkammer
hervorgerufen wird.
10. Tintenstrahldüsenanordnung nach einem der vorhergehenden Ansprüche, wobei die Anordnung
auf einem Wafer unter Einsatz von mikroelektromechanischen Techniken gebildet wird,
welcher Wafer darüber hinaus einen Tintenzufuhrkanal in Fluidverbindung mit der Düsenkammer
hat, und der Tintenzufuhrkanal durch den Wafer hindurch geätzt ist.
11. Tintenstrahldüsenanordnung nach einem der Ansprüche 1 bis 5, wobei ein Ende des Aktuatorpaddels
während des Tintenausstoßes entlang einer zweiten Wand der Düsenkammer verfährt, wobei
die zweite Wand im Wesentlichen senkrecht zur ersten Wand ist.
12. Tintenstrahldüsenanordnung nach Anspruch 11, wobei das eine Ende darüber hinaus einen
Ansatz umfasst, der dichtend an der zweiten Wand angreift.
13. Tintenstrahldüsenanordnung nach Anspruch 12, darüber hinaus einen Tintenzufuhrkanal
umfassend, der mit der Düsenkammer verbunden ist, um diese wieder mit Tinte aufzufüllen,
wobei die Verbindung einen Schlitz in einer Wand der Kammer umfasst, der im Wesentlichen
einem Ende des Ansatzes gegenüberliegend angeordnet ist.
14. Tintenstrahldüsenanordnung nach Anspruch 13, wobei der Schlitz in einer Ecke einer
dritten Wand der Kammer angeordnet ist und die zweite Wand der Kammer darüber hinaus
eine Wand des Tintenzufuhrkanals bildet.
15. Tintenstrahldüsenanordnung nach Anspruch 12, wobei der Ansatz so konfiguriert ist,
dass er den Strom von Tinte in die Düsenkammer während der Verschiebung des Aktuatorpaddels
beschränkt.
16. Tintenstrahldruckkopf mit einer Tintenstrahldüsenanordnung nach einem der vorhergehenden
Ansprüche.
1. Agencement de buse pour jet d'encre comprenant :
une chambre de buse pour stocker de l'encre à éjecter ;
et caractérisé par :
au moins une pale d'actionneur mobile formant au moins une partie d'une première paroi
de ladite chambre de buse ; et
une buse d'éjection d'encre définie dans ladite première paroi,
dans lequel l'actionnement de ladite au moins une pale d'actionneur provoque l'éjection
d'encre à partir de ladite buse.
2. Agencement de buse pour jet d'encre selon la revendication 1, dans lequel ledit actionnement
provoque un déplacement de ladite au moins une pale d'actionneur vers l'intérieur
en direction du centre de ladite chambre de buse.
3. Agencement de buse pour et d'encre selon la revendication 1 ou 2, dans lequel ladite
au moins une pale d'actionneur est actionnée au moyen d'un dispositif actionneur thermique.
4. Agencement de buse pour jet d'encre selon l'une quelconque des revendications précédentes,
dans lequel ledit dispositif actionneur thermique comprend un élément chauffant résistif
conducteur encastré dans un second matériau ayant un coefficient de dilatation thermique
élevé.
5. Agencement de buse pour jet d'encre selon l'une quelconque des revendications précédentes,
dans lequel ledit élément est un serpentin mis en forme pour permettre une dilatation
sensiblement non-empêchée dudit second matériau.
6. Agencement de buse pour éjection d'encre selon l'une quelconque des revendications
précédentes, dans lequel ladite première paroi comprend un rebord de buse et une pluralité
de pales d'actionneur fixées au rebord de buse.
7. Agencement de buse pour éjection d'encre selon la revendication 6, dans lequel lesdites
pales d'actionneur sont actionnées à l'unisson de manière à éjecter de l'encre à partir
de ladite chambre de buse via ladite buse d'éjection d'encre.
8. Agencement de buse pour jet d'encre selon la revendication 6, dans lequel lesdites
pales d'actionneur sont agencées radialement autour dudit rebord de buse.
9. Agencement de buse pour jet d'encre selon l'une quelconque des revendications 6 à
8, dans lequel lesdites pales d'actionneur forment une membrane entre ladite chambre
de buse et une atmosphère extérieure, dans lequel lesdites pales s'éloignent en s'incurvant
à partir de ladite atmosphère extérieure d e, manière à provoquer une augmentation
de pression dans ladite chambre de buse, provoquant ainsi une éjection d'encre à partir
de ladite chambre de buse.
10. Agencement de buse pour jet d'encre selon l'une quelconque des revendications précédentes,
dans lequel ledit agencement est formé sur une plaquette en utilisant des techniques
micro-électromécaniques, ladite plaquette comprenant en outre un canal d'alimentation
d'encre en communication de fluide avec ladite chambre de buse, le canal d'alimentation
d'encre étant gravé à travers ladite plaquette.
11. Agencement de buse pour jet d'encre selon l'une quelconque des revendications 1 à
5, dans lequel une extrémité dudit actionneur à pale traverse le long d'une deuxième
paroi de ladite chambre de buse pendant l'éjection d'encre, ladite deuxième paroi
étant sensiblement perpendiculaire à ladite première paroi.
12. Agencement de buse pour jet d'encre selon la revendication 11, dans lequel ladite
extrémité comprend de plus un rebord en contact de manière étanche avec ladite deuxième
paroi.
13. Agencement de buse pour jet d'encre selon la revendication 12, comprenant de plus
un canal d'alimentation d'encre interconnecté à ladite chambre de buse pour la réalimentation
d'encre vers ladite chambre de buse, ladite interconnexion comprenant une fente dans
une paroi de ladite chambre, ladite fente étant sensiblement opposée à une extrémité
dudit rebord.
14. Agencement de buse pour jet d'encre selon la revendication 13, dans lequel ladite
fente est agencée dans un coin d'une troisième paroi de ladite chambre et dans lequel
ladite deuxième paroi de ladite chambre forme en outre une paroi dudit canal d'alimentation
d'encre.
15. Agencement da buse pour jet d'encre selon la revendication 12, dans lequel ledit rebord
est configuré de manière à resserrer l'écoulement d'encre dans ladite chambre de buse
pendant le déplacement dudit actionneur à pale.
16. Tête d'impression à jet d'encre comprenant un agencement de buse pour jet d'encre
selon l'une quelconque des revendications précédentes.