Metal working – Method of mechanical manufacture – Fluid pattern dispersing device making – e.g. – ink jet
Reexamination Certificate
2000-06-02
2003-07-15
Tugbang, A. Dexter (Department: 3729)
Metal working
Method of mechanical manufacture
Fluid pattern dispersing device making, e.g., ink jet
C029S611000, C029SDIG001, C347S056000, C347S061000, C347S065000, C427S240000, C427S553000, C427S385500, C427S407100, C430S320000
Reexamination Certificate
active
06591500
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a liquid discharge head for discharging desired liquid by the creation of a bubble occurring by heat energy being caused to act on the liquid, and a method of manufacturing such liquid discharge head. Particularly the present invention relates to a method of manufacturing a liquid discharge head having a movable member displaced by the utilization of the creation of a bubble, a liquid discharge head manufactured by the same method, and a method of manufacturing a minute mechanical apparatus.
Also, the present invention can be applied to apparatuses such as a printer for effecting recording on recording mediums such as paper, yarn, fiber, cloth, metals, plastics, glass wood and ceramics, a copier, a facsimile apparatus having a communication system and a word processor having a printer portion, and an industrial recording apparatus compositely combined with various processing apparatuses.
The term “recording” in the present invention means not only imparting meaningful images such as characters and figures to the recording mediums, but also imparting meaningless images such as patterns to the recording mediums.
2. Related Background Art
FIG. 12
of the accompanying drawings is a partly broken away perspective view showing a liquid discharge head according to the prior art.
As shown in
FIG. 12
, the liquid discharge head according to the prior art has a substrate
1004
on which a plurality of heaters
1005
which are bubble creating elements for giving head energy for creating bubbles in liquid are provided in parallel, and a top plate
1001
joined onto this substrate
1004
.
The substrate
1004
comprises a base body of silicon or the like on which silicon oxide film or silicon nitride film are formed for the purposes of insulation and heat accumulation, and electrical resistance layers and wiring electrodes constituting the heaters
1005
being patterned thereon. By a voltage being applied from these wiring electrodes to the electrical resistance layers to thereby flow an electric current to the electrical resistance layers, the heaters
1005
generate heat. On the substrate
1004
, there are provided packaging electrodes
1003
to which external terminals (not shown) for supplying an electric current to the heaters
1005
are connected.
The top plate
1001
is for constituting a plurality of liquid flow paths
1007
corresponding to the heaters
1005
and a common liquid chamber
1010
for supplying the liquid to the liquid flow paths
1007
, and is integrally provided with flow path side walls
1001
a
extending from the ceiling portion thereof to among the heaters
1005
. Also, the upper surface of the top plate
1001
is provided with an ink supply communication opening
1002
for causing the liquid supplied from the outside to flow into the common liquid chamber
1010
. The top plate
1001
is formed of a silicon material, and the pattern of the liquid from paths
1007
and the common liquid chamber
1010
can be formed by etching, and the portions of the liquid flow paths
1007
can be etched and formed after a material such as silicon nitride or silicon oxide which provides the flow path side walls
1001
a
is accumulated on the silicon substrate by a conventional film forming method such as CVD.
A wall portion is provided on the fore end surface of the top plate
1001
, and this wall portion is formed with a plurality of discharge openings
1006
corresponding to the respective liquid flow paths
1007
and communicating with the common liquid chamber
1010
through the liquid flow paths
1007
.
FIG. 13
of the accompanying drawings is a partly broken away perspective view showing another example of the liquid discharge head according to the prior art.
The liquid discharge head shown in
FIG. 13
is provided with cantilever-like movable members
2009
disposed in face-to-face relationship with heaters
2005
. The movable members
2009
comprise thin film formed of a silicon material such as silicon nitride or silicon oxide or nickel or the like excellent in elasticity. These movable members
2009
are disposed at a predetermined distance from the heaters
2005
so as to have fulcrums upstream of the heaters
2005
and further have free ends downstream with respect to these fulcrums.
The top plate
2001
, the ink supply communication opening
2002
, the packaging electrodes
2003
, the substrate
2004
, the heaters
2005
, the discharge openings
2006
, the liquid flow paths
2007
and the common liquid chamber
2013
of the liquid discharge head are similar to those of the liquid discharge head shown in FIG.
12
and therefore need not be described in detail.
FIGS. 14A
to
14
D of the accompanying drawings are cross-sectional views along the direction of the flow paths for illustrating the liquid discharging method by the liquid discharge head shown in FIG.
13
.
As shown in
FIG. 14A
, when the heater
2005
is caused to generate heat, the heat acts on the ink between the movable member
2009
and the heater
2005
, whereby a bubble
2008
based on a film boiling phenomenon is created and grows on the heater
2005
. Pressure resulting from the growth of this bubble
2008
preferentially acts on the movable member
2009
, which is thus displaced so as to greatly open toward the discharge opening
2006
side about the fulcrum, as shown in FIG.
14
B. By the displacement or displaced state of the movable member
2009
, the propagation of the pressure based on the creation of the bubble
2008
or the growth of the bubble
2008
itself is directed to the discharge opening
2006
side, and the liquid (liquid droplet
2010
) is discharged from the discharge opening
2006
, as shown in FIG.
14
C.
As described above, the movable member
2009
having a fulcrum on the upstream side (the common liquid chamber side) of the flow of the liquid in the liquid flow path
2007
and having a free end on the downstream side (the discharge opening
2006
side) thereof is provided on each heater
2005
, whereby the direction of propagation of the pressure of the bubble
2008
is directed toward the downstream side and thus, the pressure of the bubble
2008
directly and efficiently contributes to discharge. The direction of growth itself of the bubble
2008
, like the direction of propagation of the pressure of the bubble, is directed toward the downstream side, and the bubble grows larger on the downstream side than on the upstream side. The direction of the growth itself of the bubble
2008
is thus controlled by the movable member
2009
to thereby control the direction of propagation of the pressure of the bubble
2008
, whereby fundamental discharge characteristics such as discharge efficiency and discharging force or discharge speed can be improved.
On the other hand, as shown in
FIG. 14D
, when the bubble
2008
enters its disappearing step, the bubble
2008
rapidly disappears by the combined effect with the elastic force of the movable member
2009
itself, and the movable member
2009
finally returns to its initial position shown in FIG.
14
A. At this time, in order to make up for the contracted volume of the bubble and to make up for the discharged volume of the liquid, the liquid flows from the upstream side, i.e., the common liquid chamber side, and the refilling of the liquid flow path
2007
with the liquid is effected, and this refilling with the liquid is effected efficiently and rationally with the returning action of the movable member
2009
.
In a method of manufacturing a liquid discharge head according to the prior art shown in
FIG. 15
of the accompanying drawings, movable members
2009
are first formed on a substrate
2004
on which heaters
2005
, etc. are provided. The movable members
2009
are made by a series of semiconductor processes comprising, for example, the formation of a sacrifice layer aluminum pattern, the formation of SiN layers forming the movable members
2009
and the patterning of the SiN layers. As described above, devices such as the movable members are pro
Iijima Yasushi
Kurihara Yoshiaki
Masukawa Tatsuya
Miyagawa Masashi
Suzuki Yoshiaki
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Tugbang A. Dexter
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